Hundreds of researchers have made significant contributions to cognitive science. What follows is a set of short academic biographies of people whom we believe should be counted on anyone's list of important contributors; the work of many of them is discussed in the Companion. Not every important figure is included; and some people are included, especially from the history of cognitive science, who would not describe, or could not have described, themselves as cognitive scientists despite their considerable impact on the field. We trust that the list will be useful to students doing research in cognitive science and to readers who wish to familiarize themselves with the work of specific contributors.

While this list has been expanded beyond that included in the Companion to Cognitive Science, it is still very incomplete. As time permits, we will add entries, but we welcome anyone who wants to supply material, either on themselves or another cognitive scientist. We would also welcome updates on anyone who is included, especially information about changes in their academic affiliation.

Abelson, Robert P. (b.1928; Brooklyn, NY; Ph.D., Psychology, Princeton, 1953). Abelson has spent his career at Yale, where he has combined his interest in mathematical psychology and social psychology by focusing on phenomena such as attitude change. He developed an early interest in the use of computers to simulate both cognitive and social processes, including, for example, the American electorate in the 1960 and 1964 elections. He is best known in cognitive science for his work with Roger Schank on computational models of story comprehension. In Scripts, Plans, Goals, and Understanding (1977), they introduced the concepts of scripts, plans and themes to handle story-level understanding. His most recent book is Statistics as principled argument (1995).

Anderson, James A. (b. 1940, Detroit, MI; Ph.D., Physiology, MIT, 1967). Anderson has spent his career at Brown University, where he is currently professor and chair of Cognitive and Linguistic Sciences at Brown. His work concentrates on applications of neural networks to such domains as human concept formation, speech perception, and models of low level vision. His framework of a brain state in a box has been influential in neural network research. In 1995 he published Introduction to Neural Networks.

Anderson, John R. (b. 1947, Vancouver, BC, Canada; Ph.D., Psychology, Stanford University, 1972). Anderson has been in the Department of Psychology at Carnegie Mellon University since 1978. With his dissertation advisor Gordon Bower, Anderson modeled declarative memory in a semantic network model (HAM) in his first book, Human Associative Memory. He is best known for his ACT theory, according to which human cognition arises as an interaction between declarative and procedural knowledge structures. The theory was intended to be a complete theory of higher-level human cognition. It was first proposed in his 1976 book Language, Memory, and Thought; a more developed version is described in The Architecture of Cognition (1983). Most recently, Anderson has been integrating research on the statistical structure of the problems solved by >subsymbolic= processes into the ACT architecture. This research has led to ACT-R theory, first described in Rules of the Mind (1993).

Babbage, Charles (b. 1791, Teignmouth, Devonshire UK, d. 1871, London, UK). Elected to the Royal Society at age 24, Babbage became Lucasian Professor of Mathematics at Cambridge in 1827. He is often referred as the father of computing in recognition of his design of two machines, the difference engine for calculating tables of logarithms by repeated additions performed by trains of gear wheels, and the analytical engine designed to perform a variety of computations using punch cards. Babbage spent much of his life trying to build the difference engine, a prototype of which was not completed until long after his death. His inventions went beyond computing and included the speedometer and the train cowcatcher. Among his best known writings are Reflections on the Decline of Science in England (1831) and On the Economy of Machinery and Manufactures (1833), the latter of which proposed an early form of operations research.

Baddeley, Alan D. (b.1934, Leeds; Ph.D., Psychology, Cambridge, 1967). Baddeley, a leading researcher on memory, spent much of his career as Director of the Applied Psychology Unit of the Medical Research Council in Cambridge, England. Among his important theoretical contributions has been the modeling of working memory in terms of an articulatory loop. His books include The Psychology of Memory (1976) and Your Memory: a User's Guide (1982), Working Memory (1986), Working Memory and Language (1993).

Ballard, Dana Harry (b. 1946; Ph.D., Computer Science, UC, Irvine, 1974). Ballard has spent his career at the University of Rochester where he is now Professor of Computer Science. His main research interest is in computational theories of the brain with emphasis on human vision. In 1985, with Chris Brown, he led a team that designed and built a high speed binocular camera control system that is capable of simulating human eye movements. This system has led to an increased understanding of the role of behavior in vision. The theoretical aspects of that system were summarized in a paper, Animate Vision, which received the Best Paper Award at the 1989 International Joint Conference on Artificial Intelligence. Dana is author of Computer Vision (1982) and Introduction to Neural Computation (1997).

Barsalou, Lawrence (b.1951, San Diego, CA; Ph.D., Psychology, Stanford, 1981). Professor of Psychology at Emory University, Barsalou=s research addresses the structure and foundation of human categorization. His early research demonstrated that goal-derived categories exhibit the same prototypicality effects that Rosch established for ordinary categories. His more recent research grounds human concepts in mechanisms that underlie dynamic processing of perceptual symbols, including how they can be incorporated into a frame structure. He is author of Cognitive psychology: An overview for cognitive scientists (1992).

Bartlett, Sir Frederick Charles (b. 1886, Stow-on-the-Wold, Gloucestershire, England, d. 1969, Cambridge, England; M.A., Moral Sciences, University of Cambridge). Bartlett spent his professional career (1922-1952) at Cambridge University, where he became the first professor of experimental psychology. He was also editor of the British Journal of Psychology from 1924 to 1948, and was knighted in 1948. Bartlett is best known for his studies of memory using meaningful materials rather than nonsense syllables. In Remembering (1932) he showed how individuals, instead of merely reproducing the materials, organized them in terms of schemata.

Bates, Elizabeth (b. 1947; Ph.D., University of Chicago, 1974). Since 1981 Bates has been at UCSD, where she is currently Professor of Psychology and Cognitive Science and directs the Center for Research in Language and the Project in Cognitive and Neural Development. Bates is a psycholinguist and developmental psychologist whose research interests include the brain bases of language in children and adults, language and cognitive development in normal and neurologically impaired populations of children, real-time language processing in monolinguals and bilinguals, and cross-linguistic comparisons of language development, language use, and language loss. She is coauthor of From First Words to Grammar (1988), The Cross-Linguistic Study of Sentence Processing (1989) Rethinking Innateness: A Connectionist Perspective on Development (1996).

Bechtel, William (b. 1951, Detroit, MI; Ph.D., Philosophy, The University of Chicago, 1977). Bechtel is a philosopher of neuroscience and cognitive science in the Philosophy-Neuroscience-Psychology Program at Washington University in St. Louis. His research focuses on strategies of theory development in the cognitive neurosciences and on relations between disciplines engaged in the study of the mind. He is editor of Philosophical Psychology and author of Philosophy of Science (1988), Philosophy of Mind (1988), Connectionism and the Mind (1990), and Discovering Complexity (1993).

Berlin, Brent (b.1936, Pampa, Texas; Ph.D., Anthropology, Stanford University, 1964). After spending most of his career at the University of California, Berkeley, Berlin is now Graham Perdue Professor of anthropology at the University of Georgia. He has conducted ethnobotanical studies among the Highland Maya of Chiapas, Mexico, and ethnobotanical and ethnozoological field work among the Jívaro of Amazonas, Peru. In collaboration with Paul Kay, Berlin examined color terms in a wide number of languages and established that there are eleven universal color categories and that these color terms enter a language in a strict order. Together they wrote Basic Color Terms: Their Universality and Evolution (1969).

Biederman, Irving. Biederman is Keck Professor of Cognitive Neuroscience at the University of Southern California where he directs the Image Understanding Laboratory. He has developed a theory of real-time human object and scene recognition that posits a representation specifying simple viewpoint-invariant shape primitives, termed geons. In collaboration with John Hummell, Biederman implemented geon theory in a neural network.

Blakemore, Colin (b. 1944, Stratford-upon-Avon, England; Ph.D., Physiological Optics, University of California, Berkeley, 1968). Blakemore has been at Oxford since 1979, where he is now Director of the Oxford Centre for Cognitive Neuroscience. His research is concerned with many aspects of vision and the early development of the brain, especially the mechanisms of stereoscopic vision, visual illusions and the perception of shape, contrast, size and form. He is author of Mechanisms of Mind (1977) and editor of Mindwaves: thoughts on intelligence, identity, and consciousness (1987), Images and understanding : thoughts about images, ideas about understanding (1990), and Vision: Coding and efficiency (1990).

Bobrow, Daniel G. (b. 1929; New York, Ph.D., Mathematics, MIT, 1964). Bobrow has spent much of his career at Bolt Beranek and Newman and Xerox Parc. In addition to developing computer languages and programming systems, he has worked on such problems in artificial intelligence as natural language processing and knowledge representation. Through his active engagement in interdisciplinary collaboration, he helped to shape cognitive science in its early decades.

Boole, George (b. 1815, Lincoln, UK, d. 1864, Cork, Ireland). Mostly self-educated, Boole spent his academic career at Queen=s College in Cork, Ireland (1849-1864). In his principal work, An Investigation of the Laws of Thought on Which Are Founded the Mathematical Theories of Logic and Probabilities (1854), Boole established a new branch of mathematics, symbolic logic, in which symbols are used to represent logical operations. In this book, Boole proposed a calculus (the Boolean algebra, in which symbols take one of only two values, 0 and 1) that he claimed was based on the nature of human logical thought. He saw his project as an attempt to translate thought into mathematical symbols.

Bower, Gordon Howard (b. 1932, Scio, OH; Ph.D. Experimental Psychology, Yale, 1959). Bower spent most of his career at Stanford University where he mentored many of the major contributors to cognitive psychology. His early work developed mathematical models of human learning, culminating in Theories of Learning, with Ernest Hilgard (1966) and Attention to Learning (1968), written with Thomas Trabasso. His work with John Anderson on human memory processes resulted in Human Associative Memory (1973). Other of his research deals with the influence of imagery, organizational factors, and emotions on memory and recall.

Bransford, John (Ph.D., Psychology, Minnesota, 1970). Bransford has spent his professional career at Vanderbilt University, where he is currently Co-Director of the Learning Technology Center. While a graduate student he collaborated with Franks in pioneering work which helped establish the importance of active cognitive processes that extracted prototypes in memory. In recent years he has concentrated on educational strategies, including strategies of problem solving. He is co-author of The ideal problem solver: a guide for improving thinking, learning, and creativity (1993).

Brentano, Franz (b. 1838, Germany, d. 1917, Zürich, Switzerland; Ph.D., Philosophy, University of Tübingen, 1862). Brentano taught at the University of Würzburg (1866-74) and the University of Vienna (1874-1895). An opponent of Wundt's emphasis on experimentation, Brentano is known especially for his appeal to intentionality or internal object-directedness of thought to mark the distinction between psychological and physical phenomena in Psychologie vom empirischen Standpunkt ("Psychology from an Empirical Standpoint," 1874).

Broadbent, Donald E. (b. 1926, Birmingham, England; d. 1993; Ph.D., Psychology, University of Cambridge). Broadbent was a researcher and director of the Applied Psychology Unit in Cambridge for a major portion of his career, before moving to Oxford in the 1970s. His research covered a wide variety of problems, from the design of postal zip codes to attention, in which he popularized the use of dichotic listening experiments. His books include Perception and Communication (1958), Decision and Stress (1971) and In Defense of Empirical Psychology (1973).

Broca, Paul (b. 1824, Sainte-Foy-la-Grande, France, d. 1880, Paris; M.D., University of Paris, 1849). Broca, who spent his career at the University of Paris (1853-1880), had wide ranging interests that included both neuroanatomy and anthropology. He is best known for his research on Laborgne, a patient who exhibited a severe deficit in articulate speech (the patient was known as Tan, since that was the one expression he could utter). Broca argued that Tan's deficit originated from a lesion in the third frontal lobe, and that this was the center for articulate speech. The area came to be referred to as Broca's area.

Brodmann, Korbinian (b. 1868, Liggersdorf, Germany, d. 1918, Munich; M.D., University of Leipzig, 1898). In research conducted between 1901 and 1910 at the Neurobiological Institute in Berlin, Brodmann argued that the human cortex is organized anatomically in the same way as the cortex of all other mammals. He showed that the cortex in animals and humans consisted of six layers, and, on the basis of anatomical differences in these layers, he developed a numbering system for areas of cortex which has become a standard basis for designating areas of cortex. His work culminated with the publication of Vergleichende Lokalisationslehre der Grosshirnrinde in 1909.

Brooks, Rodney (b. 1954, Adelaide, Australia; Ph.D., Computer Science, Stanford, 1981). Brooks joined the faculty of MIT in 1984 and is currently Fujitsu Professor of Computer Science and Director of the Artificial Intelligence Laboratory. His research is concerned with both the engineering of intelligent robots to operate in unstructured environments, and with understanding human intelligence through building humanoid robots. He argues against the need to posit representations to account for intelligent action.

Brown, Roger (b. 1925, Detroit, MI, d. 1997, Boston; Ph.D., Psychology, University of Michigan, 1952). Brown spent most of his professional career at Harvard University and is celebrated for his longitudinal study of the development of language in three children, culminating in A First Language (1973). His other major books include Words and Things (1958), Social Psychology (1965), Psycholinguistics (1970), and Psychology (1975).

Bruner, Jerome (b. 1915, New York City; Ph.D., Psychology, Harvard, 1941). Having spent the major portion of his career at Harvard, Bruner later worked at Oxford and the New School for Social Research and is currently Research Professor in Psychology and Senior Research Fellow in the School of Law at New York University. In the 1940s Bruner, together with Leo Postman, developed what came to be called the new look movement in perception which emphasized the role of active psychological processes in perception. Together with George Miller, he founded the Harvard Center for Cognitive Studies in 1960. Following A Study of Thinking in 1956, on concept acquisition, Bruner's interest turned increasingly to developmental psychology and the relation between culture and mental development. Most recently he has emphasized narrative and the nature of interpretive activity. His numerous books include Actual Minds, Possible Worlds (1987), Acts of Meaning (1991), and The Culture of Education (1996).

Buchanan, Bruce G. (b. 1940, St. Louis, MO; Ph.D., Philosophy, Michigan State University, 1966). Buchanan spent much of his career in the Computer Science Department at Stanford University, where he was co-director of the Knowledge Systems Laboratory. He moved to the University of Pittsburgh in 1988 as Co-Director of the Center for Parallel, Distributed, and Intelligent Systems. Buchanan=s research has focused on intelligent computer methods for knowledge acquisition and machine learning, scientific hypothesis formation, and construction of expert systems for scientific problems. He was one of the principal designers of a number of pioneering expert systems including DENDRAL, Meta-DENDRAL, MYCIN, E-MYCIN, and PROTEAN.
 
 

Cajal, Santiago Ramón y (b. 1852, Petil-la de Aragón, Spain, M.D., Zaragoza, d. 1934). Cajal held chairs in Descriptive and General Anatomy at the University of Valencia and in Histology and Pathological Anatomy at the Universities of Barcelona and Madrid. In 1887 Cajal learned of Golgi silver stain, which he employed widely to describe various kinds of neurons. Convinced that neurons were individual cells, he championed the neuron doctrine. In his later work he focused on the degeneration and regeneraton of the nervous system. Cajal shared the 1906 Nobel Prize for Physiology or Medicine with Golgi.

Caramazza, Alfonso (Ph.D., Psychology, Johns Hopkins, 1974). In addition to serving on the Psychology faculty at Johns Hopkins, Caramazza helped found the Cognitive Science Department. Since 1995 he has been in the Psychology Department at Harvard. His research involves the neuropsychology of language processes, psycholinguistics, naive physics, and mechanisms of visual neglect. He is a critic of the neural-localizationist assumptions of classical models of language processing, such as Norman Geschwind's, arguing that such models cannot account for patterns of aphasia observed in patients with lesions. Instead, according to Caramazza, researchers should focus on the types of representations and processing mechanisms that implement such functions.

Carbonell, Jaime G. (Ph.D., Computer Science, Yale, 1976). Carbonell is Professor of Computer Science and the Director of the Center for Machine Translation at Carnegie-Mellon University. His research interests span knowledge-based machine translation, machine learning, natural language processing, planning, and problem solving.

Carey, Susan (Ph.D., Psychology, Harvard, 1971). After spending much of her career at MIT, Carey is now Professor of Psychology at New York University. Her research concentrates on cognitive development and knowledge acquisition. Two major foci of her work have been the construction of intuitive biology and intuitive physics in early childhood and relations between prelinguistic conceptual structure and lexical structure.

Carpenter, Patricia (Ph.D., Psychology, Stanford, 1972). Carpenter, Professor of Psychology at Carnegie Mellon University, seeks to address the question: Why is it that some people are good at solving spatial problems but are unable to express themselves in words, whereas others may write with fluency and ease, but have difficulty navigating with a road map? Carpenter investigates the functional characteristics and neural processes that underlie complex cognitive skills, such as mental imagery, problem solving, and language, using a variety of methodologies including behavioral studies, brain imaging, computer simulation, and neuropsychological studies of certain patients.

Charniak, Eugene (b.1946; Ph.D., Computer Science, M.I.T., 1972). Charniak is professor of Computer Science and Cognitive Science at Brown University. His research addresses language understanding or technologies which relate to it, such as knowledge representation, reasoning under uncertainty, and learning. Recently he has explored statistical techniques for language understanding, including part-of-speech tagging, probabilistic context-free grammar induction, syntactic disambiguation through word statistics, efficient syntactic parsing, and lexical resource acquisition through statistical means. Charniak was a founding editor of Cognitive Science; among his books are Artificial Intelligence Programming (1987) and Statistical Language Learning (1993).

Chomsky, A. Noam (b. 1928, Philadelphia; Ph.D., Linguistics, University of Pennsylvania, 1955). Chomsky, who has spent his professional career at MIT, catalyzed a revolution in linguistics with his development of transformational grammars and arguments as to the shortcomings of statistical approaches to modeling grammatical knowledge. In 1959 he published a review of B. F. Skinner's Verbal Behavior in which he argued that language acquisition could not be explained with the resources of the classical theory of conditioning, and required the positing of representational structures governed by rules. Throughout his career Chomsky has regularly revised his accounts of grammar in the attempt to provide a more satisfactory account of acceptable linguistic structures. Chomsky has also been an ardent defender of a nativist account of our knowledge of grammar. Among his numerous publications are the following influential books: Syntactic Structures (1957), Aspects of the Theory of Syntax (1965), Cartesian Linguistics (1966), Language and the Mind (1968), Rules and Representations (1980), Lectures on Government and Binding (1981) and The Minimalist Program (1995).

Church, Alonzo (b. 1903, Washington, DC, d. 1995, Hudson, OH; Ph.D., Mathematics, Princeton, 1927). A faculty member at Princeton University from 1929 to 1967 and at the University of California at Los Angeles from 1967 until 1990, Church, one of the foremost logicians of the 20th century, created the lambda calculus in the 1930's, which today is an invaluable tool for computer scientists. He is best remembered for Church's Thesis that any effectively decidable function can be represented as a recursive function, as well as Church's Theorem (1936), which shows there is no decision procedure for arithmetic.

Churchland, Patricia S. (b. 1943, Oliver, British Columbia, Canada; D. Phil., Philosophy, Oxford, 1969). After 25 years at the University of Manitoba, P. S. Churchland has been Professor of Philosophy at UCSD since 1984. She has been an avid proponent of a reductionistic approach to mind; in Neurophilosophy (1986), a landmark book integrating philosophy with neuroscience, she defends a coevolution of mind and brain in which future psychological accounts will reduce to neuroscientific ones. She has collaborated in empirical work, in particular with T. Sejnowski, with whom she authored The Computational Brain (1992).

Churchland, Paul M. (b.1942, Vancouver, British Columbia, Canada; Ph.D., Philosophy, University of Pittsburgh, 1969). After a lengthy stint at the University of Manitoba, P. M. Churchland become Professor of Philosophy at UCSD in 1984. Churchland has been a major advocate of eliminitivism, the doctrine that our everyday, common-sense, >folk= psychology, which seeks to explain human behavior in terms of the beliefs and desires of agents, is actually a deeply flawed theory that must be eliminated in favor of a mature cognitive neuroscience. Churchland first suggests this thesis in his 1979 book Scientific Realism and the Plasticity of Mind. In the 1980s, Churchland began to champion connectionism as a source of answers to traditional problems in the philosophy of mind and of science. His connectionist insights are presented in A Neurocomputational Perspective (1989); his latest book, The Engine of Reason, The Seat of the Soul (1995), extends his view to the social and moral dimensions of human life.

Cicourel, Aaron V. (b. 1928, Atlanta, Georgia; Ph.D., Anthropology and Sociology, Cornell University, 1957). Cicourel has been at UCSD since 1970, where he is now Professor of Cognitive Science, Pediatrics, and Sociology. A pioneer in relating cognitive science and sociology, Cicourel has concentrated on the local, ethnographically situated use of language and thought in natural settings. His 1974 book, Cognitive Sociology: Language and Meaning in Social Interaction, helped define this research area. His conviction that cognition is always embedded in cultural beliefs about the world and in local social practices has recently led him to explore the connections between neural development in children, human information processing and the way socially organized ecologies influence the brain's internal organization and the child's capacity for normal problem solving, language use, and emotional behavior.

Clark, Andy (b. 1957, London, England; Ph. D., Philosophy, University of Stirling, Scotland, 1984). Clark is Professor of Philosophy and Director of the Philosophy/Neuroscience/Psychology program at Washington University in St. Louis, Missouri. His previous position was as Reader in Philosophy with Cognitive Sciences at the University of Sussex, Falmer, Brighton, U.K. His main interest lies in the implications of developments in connectionism, dynamical systems, and artificial life for a variety of conceptual and philosophical issues. He is the author of three books: Microcognition (1989), Associative Engines (1993), and Being There: Putting Brain, Body and World Together Again (1996).

Clark, Eve V. (b. 1942, Camberley, UK; Ph.D., Linguistics, Edingurgh, 1969). E. V. Clark has been in the Department of Linguistics at Stanford University since 1969. Her research has focused on language acquisition, word-formation, and lexical structure. For over 25 years she has directed the Child Language Research Forum at Stanford University and helped to edit its proceedings. Her books include Psychology and Language (1977), The Ontogenesis of Meaning (1979), Acquisition of Romance, with Special Reference to French (1985), and The Lexicon in Acquisition (1993).

Clark, Herbert H. (b. 1940, Deadwood, SD; Ph.D., Psychology, Johns Hopkins University, 1966). Clark has been in the Department of Psychology at Stanford University since 1969, where he has investigated the cognitive and social processes in language use. He is especially interested in the interactive processes of conversation, which range from low-level disfluencies through acts of speaking and understanding to the emergence of discourse. He is also interested in word meaning and word use. His books include Psychology and Language (1977), Arenas of Language Use (1992) and Using Language (1996).

Collins, Allan (b. 1937, Orange, NJ; Ph.D., Cognitive Psychology, University of Wisconsin, 1970). Collins has spent most of his career as a research scientists at Bolt Beranek and Newman; since 1989 he has also been Professor of Education and Social Policy, Northwestern University. He is best known in psychology for his work on semantic memory and mental models, in artificial intelligence for his work on plausible reasoning and intelligent tutoring systems, and in education for his work on inquiry teaching, cognitive apprenticeship, situated learning, epistemic games, and systemic validity in educational testing. Collins was one of the founding editors of Cognitive Science.

Craik, Fergus I. M. (b.1935, Edinburgh, Scotland; Ph.D. Liverpool, 1965). Craik has spent his professional career in the Psychology Department at the University of Toronto; he is now also affiliated with the Rotman Research Institute. Much of Craik's research has focused on memory, and he is perhaps best known for the concept of "levels of processing," which he and Robert Lockhart advanced in 1972 as an alternative to the hypothesis of separate stages for sensory, working and long-term memory. According to the levels of processing framework, stimulus information is processed at multiple levels simultaneously depending upon its characteristics and the "deeper" the processing, the more that will be remembered..
 
 

Damasio, Antonio R. (b.1944, Lisbon, Portugal; M. D. and Ph.D., University of Lisbon, 1969, 1974). Currently, Damasio is M. W. Van Allen Professor and head of the Department of Neurology at the University of Iowa. His research in cognitive neuroscience has focused on large-scale neural systems and their role in mental function. Through his semantic marker hypothesis, he draws an intimate connection between emotion and cognition. His research on patients with frontal lobe damage, reviewed in his book Descartes' Error (1994), indicates that covert signals or overt feelings normally accompany response options and operate as a bias to assist knowledge and logic in the process of choice.

D'Andrade, Roy Goodwin (b. 1931, Brooklyn, NY; Ph.D., Social Relations, Social Anthropology, Harvard, 1962). Since 1970 D=Andrade has been in the Department of Anthropology at UCSD. Early in his career he collaborated on a cognitively oriented computational analysis of kin terms and pioneered the use of scaling and other statistical techniques in anthropological linguistics. Later he used comparative cognitive studies to explore the cultural components of cognition. His books include The Development of Cognitive Anthropology (1995).

de Groot, Adriaan D. (b. 1914; Haarlem, The Netherlands; Ph.D., Psychology, University of Amsterdam). His early work on cognition, and in particular his thesis Het denken van den schaker (English translation, Thought and Choice in Chess, 1965), became an inspiration for later cognitive researchers such as Herbert Simon. In particular, de Groot highlighted the importance in of the ability to organize or chunk information in strategic ways in order to achieve expert performance in chess.
 
 

Dennett, Daniel (b. 1942; D.Phil., Philosophy, Oxford, 1965). Dennett has spent most of his career at Tufts University, where he is now Director of the Center for Cognitive Studies. In his book The Intentional Stance (1987) he argues that intentionality can be explained in terms of a stance that we are forced to take toward complex, adaptive systems that behave rationally. His 1991 book Consciousness Explained argues that consciousness can be identified with a covert stream of internalized discourse. Other important works by Dennett include Content and Consciousness (1969), Brainstorms (1979), Elbow Room (1984), and Darwin=s Dangerous Idea (1995).

Donders, Franciscus Cornelius (b.1818, Tilburg, the Netherlands; d. 1889; M.D., Utrecht). Spending most of his professional career at the University of Utrecht, Donders developed the subtractive method whereby the time taken to complete one activity was subtracted from the time taken to complete another activity thought to differ in just one operation so as to determine the time required for the additional operation.
 

Dreyfus, Hubert L. (b. 1929, Terre Haute, IN; Ph.D., Philosophy, Harvard, 1964). Spending most of his professional career at the University of California, Berkeley, Dreyfus has for 30 years been a leading critic of AI. His critique draws upon continental philosophy and emphasizes embodiment of cognitive systems against an overly rationalist representational approach. His major books are: What Computers Can=t Do: The Limits of Artificial Intelligence (1972), What Computers Still Can't Do: A Critique of Artificial Reason (1992) and Mind Over Machine (1986).
 
 

Dyer, Michael G. (b. Washington, DC; Ph.D., Computer Science, Yale, 1982). Dyer is Director of the Artificial Intelligence Laboratory at UCLA. His research focuses on symbolic, connectionist, and genetic algorithm models of natural language processing and acquisition.
 
 

Ebbinghaus, Hermann (b. 1850, Wuppertal, Germany, d. 1909, Halle, Germany; Ph.D., Philosophy, University of Bonn, 1873). Ebbinghaus spent the major part of his career at the University of Berlin and the University of Breslau. In pursuit of his ambition to apply the scientific method to the study of higher cognitive processes, Ebbinghaus invented a new method for the study of memory. Using himself as sole subject, he learned lists of nonsense syllables to mastery and recorded the amounts retained, or the trials necessary for relearning, after a passage of time. His major work was Über das Gedächtnis (1885, English translation, Memory, 1913). To publish work emanating from places other than Wundt=s Leipzig laboratory, Ebbinghaus and König founded the Zeitschrift für Psychologie und Physiologie der Sinnersorgane in 1890.
 
 

Elman, Jeffrey (b. 1948, Los Angeles, CA; Ph.D., Linguistics, University of Texas, at Austin, 1977). Elman has spent his professional career at UCSD where he is now professor of Cognitive Science. He developed a technique of employing recurrent (backwards) connections in connectionist networks and has used connectionist models to study language processing and development; he is co-author of Rethinking Innateness: A Connectionist Perspective on Development (1996).

Farah, Martha J. (b. 1955, New York City; Ph.D., Experimental Psychology, Harvard, 1983). Farah has pursued research in neuropsychology of visual processing and imagery, first at Carnegie Mellon University, and now at the University of Pennsylvania. In 1990 she published Visual agnosia, a study that used deficits in object recognition to understand normal visual processing.

Fechner, Gustav Theodor (b. 1801, Gross-Sächen, Prussia, d.1887, Leipzig; M.D., University of Leipzig, 1822). Fechner spent much of his career at the University of Leipzig, first as Professor of Physics, then as Professor of Philosophy. Fechner was a pioneer in psychophysics, measuring sensation indirectly in units corresponding to the just noticeable differences between two sensations; the reports of his studies constitute a large part of the first of the two volumes of the Elemente der Psychophysik. Expanding on the earlier work of Ernst Weber, Fechner's law holds that the intensity of a sensation increases as the log of the stimulus (S = k log R).
 
 

Feigenbaum, Edward A. (b. 1936, Weehawken, NJ; Ph.D., Industrial Administration, Carnegie Mellon University, 1960). Feigenbaum founded the Heuristic Programming Project in the Department of Computer Science at Stanford in 1965, where he continues research directed toward developing a general framework for modeling physical devices that supports reasoning about their designed structure, intended function, and actual behavior. He collaborated with Joshua Lederberg and Bruce Buchanan in developing DENDRAL, a pioneering expert system that could identify an organic compound by analyzing mass spectrography data.

Ferrier, Sir David (b. 1843, Aberdeen, Scotland, d. 1928, London; M.D., University of Edinburgh, 1868). A professor of medicine and neuropathology at King=s College, London, Ferrier refined a technique for using mild electrical stimulation of brain areas to determine their function. In 1876 Ferrier published The Functions of the Brain, followed by Cerebral Localization in 1878.

Flanagan, Owen (b. 1949, Bronxville, NY; Ph. D. Philosophy, Boston University, 1977). After spending much of his career in the Philosophy Department at Wellesley College, Flanagan now hold appointments in philosophy, psychology, and neurobiology at Duke. Flanagan has been a major proponent of a naturalized approach to consciousness and of relating psychology to moral theory; his books include The Science of the Mind (1991), Varieties of Moral Personality: Ethics and Psychological Realism (1991), Consciousness Reconsidered (1992), and Self Expressions: Mind, Morals, and the Meaning of Life (1996).

Flourens, Marie-Jean-Pierre (b. 1794, Maureilhan, France, d. 1867, Montgeron, France; M.D., University of Montpellier, 1813). Flourens spent his career at the Collège de France (1828-1867). A staunch opponent of neural localization of brain function, Flourens developed the technique of precise extirpation or ablation of cortical tissue. He found that the quantity of cerebral tissue removed was more important than its location. His work led to Phrenology Examined, which criticized the localization claims of Gall and Spurzheim and dealt their movement a major blow.

Fodor, Jerry A. (b. 1935, New York City; Ph.D. Philosophy, Princeton, 1960). Until 1986 Fodor was on the faculty at MIT, where he became an early expositor of Chomsky's program in linguistic, collaborated in psycholinguistic research, and developed his own strongly nativistic theory. Fodor defended the claim that thinking invokes a language-like medium in The Language of Thought (1975). His 1983, book The Modularity of Mind, defends a strong version of faculty psychology, according to which the mind consists of informationally encapsulated, low-level perceptual modules which feed information to higher-level central cognitive processes are non-modular. According to Fodor, only modular cognitive processes can be studied scientifically. Since moving to Rutgers University in 1988, Fodor has been an ardent critic of connectionist models of cognitive phenomena, arguing that they cannot account for the rationality of thought.

Frege, Gottlob (b. 1848, Wismar, Germany, d. 1925, Bad Kleinen, Germany; Ph.D., Mathematics, University of Göttingen, 1873). Frege taught at the University of Jena his entire career. A pioneer in modern logic, he constructed the first predicate calculus, developed a new analysis of basic propositions and quantification, formalized the notion of a proof in terms that are still accepted today, and demonstrated that one could resolve theoretical mathematical statements in terms of simpler logical and mathematical notions. To ground his views about the nature of logic, Frege conceived a comprehensive philosophy of language that introduced the important distinction between the sense and reference of linguistic terms.

Freeman, Walter J., (b. 1927, Washington, DC; M.D., Yale, 1954). Since 1959 Freeman has been at the University of California, Berkeley, first in physiology and now in neurobiology. Freeman employs EEG and single unit recording to study cortical responses during goal directed activity. His models of cortical activity using non-linear differential equations, especially his models of the olfactory bulb, have been influential in promoting the dynamical systems approach to cognition.

Friedlander, Michael (b. 1950, Miami, FL; Ph.D., Physiology and Biophysics, University of Illinois, 1977). Friedlander has been at the University of Alabama at Birmingham since 1980, where he is now Chair of the Department of Neurobiology. Friedlander studies the fundamental biological processes that regulate the synthesis, assembly and retention of information in visual perception in the cerebral cortex.

Gall, Franz Joseph (b. 1759, Tiefenbrunn, Baden, d. 1828, Paris, France; M.D., University of Vienna, 1785). Gall practiced medicine in Vienna from 1785 to 1807, and in Paris from 1807 to 1828. Gall developed a program correlating protrusions in the skull with psychological faculties, an approach he called organology but which his sometimes collaborator Spurzheim called phrenology. Between 1810 and 1819 Gall published Anatomie et physiologie du système nerveux en général in four volumes (the first two written with Spurzheim), of which the last three presented the phrenological doctrine. Between 1823 and 1825 Gall published his definitive statement on phrenology, a six-volume work entitled Sur les fonctions du cerveau.

Gallistel, C. Randy (b. 1941, Indianapolis, IN; Ph.D., Psychology, Yale, 1966). Gallistel spent his career before 1989 at the University of Pennsylvania; subsequently he has been a professor in the Department of Psychology at UCLA. His books, The Organization of Action (1980) and The Organization of Learning (1990), aim to establish a broad conceptual framework for understanding the neural basis of learning and motivation, which are his primary interests. He has also written extensively on animal cognition, with particular focus on the representation of space, time, and number, and the role these representations play in determining animal behavior.

Gallup, Gordon Graham (b. 1941, Denver, CO; Ph. D., Psychology, Washington State University, 1968). Gallup has been in the Department of Psychology at Tulane University since 1968. His work addresses cognitive processes in animals; his 1968 study of chimpanzee self-recognition in mirrors has been construed as demonstrating that they posses self-consciousness
 

Gazzaniga, Michael S. (b. 1939, Los Angeles; Ph.D., Psychobiology; California Institute of Technology, 1964). Having held faculty positions at Cornell Medical College and the University of California at Davis, Gazzaniga is currently David T. McLaughlin Distinguished Professor and Director of the Program in Cognitive Neuroscience at Dartmouth College. Gazzaniga has been a leading investigator of cognitive disruptions arising in patients whose hemispheres have been disconnected through commissurotomy. He has also been one of the major institution builders in cognitive neuroscience, having founded the Journal of Cognitive Neuroscience, the Society for Cognitive Neuroscience, Chief Organizer for McDonnell Summer Institute in Cognitive Neuroscience, and edited The Cognitive Neurosciences (1995). Among his many books are The Bisected Brain (1970), The Social Brain (1985), Mind Matters (1988),and Nature's Mind (1992).

Gelman, Rochel (b. 1942, Toronto, Canada; Ph. D., Development Psychology and Learning, UCLA). After two decades in the psychology department at the University of Pennsylvania, Gelman moved to UCLA in 1989. She specializes in cognitive development and conceptual change, with an emphasis on the nature of early, universal mathematical and causal reasoning, and whether these do or do not facilitate later domain-relevant learning. Together with C. R. Gallistel, Gelman wrote The Child=s Understanding of Number (1978/1986).

Gentner, Dedre (Ph.D., Psychology, UCSD, 1974). Gentner, previously Senior Scientist at Bolt Beranek and Newman and now Professor of Psychology at Northwestern University, has authored many influential papers on analogy, metaphor and similarity, as well as a book on mental models. Her research interests also include computational simulation of comparison processes and studies of analogy and similarity in cognitive development, as well as cross-linguistic investigations of language and thought
 

Gibson, Eleanor J. (b. 1910, Peoria, Illinois; Ph.D., Psychology, Yale University, 1938). Gibson, who spent most of her professional career at Cornell University, articulated an ecological perspective in developmental psychology: perceptual development was construed as a process of differentiation, and perceptual learning as an active process of information pickup. The perceptual world is not constructed by processes of association and inference; rather, the infant explores the array of stimulation, searching for invariants that reflect the permanent properties of the world and the persisting features of the layout and of the objects in it. What comes to be perceived are the affordances for action made available by places, things, and events in the world. These ideas are expressed in Principles of Perceptual Learning and Development (1969) and An Odyssey in Learning and Perception (1991)
 

Gibson, James J. (b. 1904, McConnelsville, OH, d.1979, Ithaca, NY; Ph.D., Psychology, Princeton, 1928). From 1928 to 1949 Gibson taught at Smith College; he then moved to Cornell University where he remained for the rest of his career. Gibson is primarily known as the founder of the ecological approach to the study of perception, an approach which emphasized the importance of rich, structured information that is already in the light reaching the retina. Subjects merely had to pick up this information, not construct it through information processing. Gibson laid out this approach in several books, including The Perception of the Visual World (1950), The Senses Considered as Perceptual Systems (1966), and The Ecological Approach to Visual Perception (1979).

Gigerenzer, Gerd (Ph.D., Psychology, Munich, 1977). Director of the Max Planck Institute for Human Development, Berlin, Gigerenzer's research focuses on bounded rationality, social intelligence, and ecological rationality.

Gilligan, Carol (b. 1936, New York City; Ph.D., Clinical Psychology, Harvard, 1964). Gilligan has spent her professional career at Harvard. She challenged Lawrence Kohlberg's pioneering studies of moral development, which had focused exclusively on males. In In a different voice: Psychological theory and women's development (1982), she argued that women often exhibit a different pattern of moral development, resulting in an emphasis on caring rather than adherence to rules. More generally, she has shown that mature moral development often involves an integration of both care and rule perspectives.

Gleitman, Henry (b. 1925, Leipzig, Germany; Ph.D., Psychology, University of California, Berkeley, 1947). Already legendary as a teacher and integrator of psychology at Swathmore College, H. Gleitman then moved to the University of Pennsylvania 35 years ago. His research focuses on cognitive processes, especially those involved in memory and language, social cognition and the psychology of drama and humor. He wrote two of the most highly regarded introductory texts in psychology, entitled Psychology (1981/1995) and Basic Psychology (1983/1996), and (with L. Gleitman) wrote Phrase and Paraphrase.

Gleitman, Lila R. (b. 1929, Brooklyn, NY; Ph.D., Linguistics, University of Pennsylvania, 1967). L. Gleitman has spent her career at the University of Pennsylvania, where she is currently Professor of Psychology and Co-Director of the Institute for Research in Cognitive Science. Noted for bringing a Chomskian perspective to bear on language acquisition research, she and her students have challenged conventional wisdom by showing that simplifications in speech to children do not enhance acquisition and that language development is robust in blind and deaf children. Most recently she is a proponent of syntactic bootstrapping. She is the co-author of Phrase and Paraphrase (1971) and Language and Experience: Evidence from the Blind Child (1985).

Goldman-Rakic, Patricia (b. Salem, Massachusetts; Ph.D., Experimental Psychology, UCLA). After over a decade at the National Institutes of Mental Health, Goldman-Rakic moved to Yale School of Medicine in 1979. Her research focuses on the development, organization, and cognitive functions of the frontal lobe, especially the role of areas of prefrontal cortex in working memory.

Golgi, Camillo (b. 1843, Cortona, Tuscany, d. 1926, Pavia, Lombardy; M.D., University of Pavia, 1865). Golgi spent his entire career, from 1875 to 1926, at the University of Pavia. He received the Nobel Prize in physiology and medicine in 1906 for his work developing a silver nitrate that stains whole nerve cells, but only a few in a preparation. It thereby makes it possible to visualize individual neurons. Although the Golgi stain played a critical role in establishing the neuron doctrince, the view that the nervous system is comprised of discrete cells, Golgi never accepted it. He continued to defend instead the reticular theory that posited a continuous reticulum in which what we construe as cell bodies were nodes that perhaps served a nutritive function. Golgi shared the 1906 Nobel Prize for Physiology or Medine with Cajal, who had employed the Golgi's stain in support of the neuron doctrine.

Goodman, Nelson (b. 1906, Summerville, Mass.; Ph.D., Philosophy, Harvard, 1941). After teaching at Tufts, Pennsylvania, and Brandeis, Goodman completed his career at Harvard University. He argued that induction was governed by pragmatic considerations as to whether the predicates employed are sufficiently entrenched in our practice. He also contributed to aesthetics, arguing that the relation between pictures and what they picture is, like the relation between words and their referents, essentially arbitrary. His major works include The Structure of Appearance (1951), Fact, Fiction, and Forecast (1955), and Ways of Worldmaking (1978).

Gopnik, Alison (b. 1955, Philadelphia PA; D. Phil., Experimental Psychology, Oxford, 1981). After a period at the University of Toronto, Gopnik has been in the Department of Psychology at the University of California, Berkeley, since 1988. Her research interests include cognitive development, language development, and the relation between philosophy and psychology; she is especially known for her work on children's acquisition of a theory of mind. She is author of Words, Thoughts and Theories (1997).

George Graham (b. 1945, Brooklyn, NY; Ph.D., Philosophy, Brandeis, 1975). Graham has been at the University of Alabama at Birmingham since 1975, where he became chair of the philosophy department in 1984. Much of his early work was directed at promoting behavioral psychology as a subject of philosophical study. He served as editor of the journal Behaviorism, changing its name to Behavior and Philosophy. Graham co-edited Philosophical Psychopathology (1994) with G. Lynn Stephens and has been working on psychopathology as a research area within both philosophy and cognitive science. He has a book forthcoming with Stephens on pathologies of self-consciousness. His books include Person to Person (1989) and Philosophy of Mind (2nd edition, 1998).

Gregory, Richard L. (b. 1923, London; D. Sc., Experimental Psychology, Bristol). After reading philosophy and psychology at Cambridge under Sir Frederick Bartlett, Gregory pursued his research on perception at Cambridge (where he directed the Special Senses Laboratory), Edinburgh (where he helped found the Department of Machine Intelligence), and the University of Bristol, (where he was the Director of the Brain and Perception Laboratory and founded of the Exploratory, a hands-on science center). Partly on the basis of studying responses to illusions, he has defended the view that perception involves predictive hypotheses much like those employed in science. Gregory founded the international journal Perception in 1973; his books include Eye and Brain (1966), The Intelligent Eye (1970), Illusion in Nature and Art (1973), Mind in Science (1981) and Odd Perceptions (1986).

Griffin, Donald R. (b. 1915, Southampton, New York; Ph.D., Biology, Harvard, 1942). During his career, Griffin worked at Cornell, Harvard, and Rockefeller University. As an undergraduate, he discovered that bats perceive the world using sonar, and much of his career was spent trying to understand their use of sonar to guide navigation. Later in his career Griffin argued for a mentalistic approach to animal cognition, defending the claim that other species experience the world in ways similar to our own. His major books include The Question of Animal Awareness (1976), Animal Thinking (1984), and Animal Minds (1992).

Grossberg, Stephen (b. 1939, New York City; Ph.D., Mathematics, Rockefeller, 1967). Much of Grossberg=s career has been spent at Boston University, where he directs the Center for Adaptive Systems. Grossberg has been a pioneer in the development of neural networks and is especially known for his adaptive resonance theory (ART) models. His books include Studies of Mind and Brain (1982) and Pattern Recognition by Self Organizing Neural Networks (1991).

Harlow, Harry F. (b. 1905, Fairfield, Iowa, d. 1981, Tucson, AZ; Ph.D., Experimental Psychology, Stanford University, 1930). From 1930 to 1974, Harlow was director of the Primate Laboratory at the University of Wisconsin, which he founded. There, he conducted research on learning, motivation, the affectional systems, and the effects and treatment of social isolation in rhesus monkeys. Harlow's work on learning resulted in the development of the concept of learning set (learning how to learn), the Wisconsin General Test Apparatus for studying problem solving, and the error-factor learning theory, which postulates that learning takes place as various tendencies that make for errors are gradually eliminated. Harlow was also one of the first researchers to demonstrate that cognitive motives, such as exploration and curiosity theretofore neglected by psychologists were as important determiners of behavior as deficiency motives like hunger.

Harris, Zelig S. (b. 1909, Balta, Russia; Ph.D., Linguistics, Pennsylvania, 1934). Harris spent his academic career at the University of Pennsylvania, where he established the first department of linguistics in the United States. He was a major contributor to what is known as structural linguistics; and is particularly known for his work on discovery procedures and the progress he made in extending the structural approach to syntax (a project carried further by his student, Noam Chomsky). His books include Methods in Structural Linguistics (1951), Mathematical Structures of Language (1968), A Grammar of English on Mathematical Principles (1982), and Language and Information (1988).

Hebb, Donald O. (b. 1904, Chester, Nova Scotia, Canada, d. 1985; Ph.D., Psychology, Harvard University, 1936). Hebb spent most of his academic career at McGill University in Montreal, where he became an influential theorist concerned with the relation between the brain and behavior. His most important book, The Organization of Behavior (1949), emphasized the formation of cell-assemblies in brain processing. He posited what is now known as Hebbian learning in which the connections between neurons are strengthened if they are simultaneously active.

Hinton, Geoffrey (b. 1947, Wimbledon, England; Ph.D., Artificial Intelligence, University of Edinburgh, 1978). After appointments at UCSD and Carnegie-Mellon, Hinton spent from 1987 to 1998 in the departments of Computer Science and Psychology at the University of Toronto; he is now moving to the University of London. Hinton has been a major contributor to the development of connectionism, helping to develop the back-propagation learning algorithm, Boltzmann machines, distributed representations, time-delay neural nets, and unsupervised learning procedures.

Hitzig, Eduard (b. 1838, Berlin, Germany, d. St. Blasien, Baden, 1907; M.D., University of Berlin, 1862). Hitzig practiced medicine in Berlin from 1862 to 1875; subsequently he directed asylums of the University of Zurich and the University of Halle. In 1870, with Gustav Fritsch, Hitzig established the electrical excitability of brain tissue by demonstrating that mild electric currents applied to specific brain locations in the dog resulted in particular muscular contractions.

Holland, John H. (b. 1929, Fort Wayne, IN; Ph.D., Computer Science, University of Michigan, 1959). Holland has spent his academic career at the University of Michigan, where he holds academic appointments in both computer science and psychology; he is also an external faculty member at the Santa Fe Institute. His research has addressed the adaptive character of cognitive processes and he is the creator of the genetic algorithm, which uses processes comparable to those of biological evolution to arrive at computer programs that are well adapted to their tasks. His research on genetic algorithms is presented in Adaptation in Natural and Artificial Systems: An Introductory Analysis with Applications to Biology, Control, and Artificial Intelligence (1975/1992). Other books include Induction: Processes of Inference, Learning, and Discovery (1986), Hidden Order: How Adaptation Builds Complexity (1995) and Emergence: From Chaos to Order (1998).

Holyoak, Keith J. (b. 1950, Ph.D., Stanford, 1976). Holyoak, who is professor of psychology at UCLA, investigates reasoning and problem solving, especially the role of analogy in thinking. Holyoak is editor of Cognitive Psychology. His books include Induction : processes of inference, learning, and discovery (1986) and Mental leaps : analogy in creative thought (1995).

Hopfield, John (b. 1933, Chicago; Ph.D., Physics, Cornell, 1958). A distinguished physicist who is currently professor of chemistry and biology at the California Institute of Technology, Hopfield previously held positions at Bell Laboratories, the University of California at Berkeley, and Princeton. Hopfield proposed a design for a neural network modeled on a spin glass, a type of physical system in which each atom in a matrix of atoms spins pointing up or down, influencing the spin of its neighbors until the matrix reaches a stable configuration. In the neural networks, known as Hopfield nets, units influence the activation of their neighbors until a stable configuration is achieved.

Hubel, David (b. 1926, Windsor, Ontario; M.D., McGill, 1951). Hubel spent most of his career at Harvard, where he often collaborated with Torsten Wiesel. Together they showed that individual neurons in visual cortex responded optimally to specific stimuli: a line or edge at a particular orientation and, for the lowest-level neurons, particular locations. They also found that cells are organized in ocular dominance columns; series of columns alternative between responsiveness to the right and left eyes. Other research focused on binocular vision and the importance of early visual stimulation to normal development. In 1981 they shared the Nobel Prize for Medicine and Physiology.

Hull, Clark (b. 1884, near Akron, NY, d. 1952, New Haven, CT; Ph. D., Psychology, University of Wisconsin, 1918.) Hull spent the major part of his career at Yale University. Having become convinced that psychology should become an exact natural science that described behavior in precise quantitative terms, Hull adopted the conceptual framework of the logical positivists. Accordingly, he developed his theories of learning as deductive systems; while considered a behaviorist, Hull=s learning theory allowed for internal variables, including drive. His major works were Principles of Behavior (1943) and A Behavioral System (1952).

Jackendoff, Ray S. (Ph.D., Linguistics, MIT, ). Jackendoff, professor of linguistics at Brandeis University, has used his studies of the semantics of natural languages to launch wide-ranging inquires into the nature of mind and language. His recent books include Consciousness and the Computational Mind (1987), Semantic Structures (1990), Languages of the Mind (1992) and Patterns in the Mind (1994).

Jackson, John Hughlings (b. 1835, Providence Green, Hammerton, England, d. 1911, London, England; M.D., St. Andrews University, 1860). Jackson spent most of his career at the National Hospital in Queen Square, London, where he conducted pioneering studies of epilepsy, aphasia, and paralysis. He rejected simple localizationist schemes in favor of a hierarchy of representations in cortex, with higher levels modulating the behavior of lower levels.

Jacoby, Larry L. (Ph.D. Southern Illinois). Jacoby, who has held positions at several universities in the United States and Canada, is now in the department of psychology at New York University. His research addresses issues involving memory; in particular, he has emphasized implicit measures of memory which detect that information that one does not consciously recall, is yet remembered.

James, William (b. 1842, New York, NY, d. 1910, Chocorva, New Hampshire; M.D., Harvard University, 1871). James spent his career at Harvard, switching his appointment between physiology, philosophy, and psychology. He established the first American demonstration laboratory for psychology in 1875 and wrote The Principles of Psychology (1890). This landmark textbook for the new field of psychology covered such topics as brain function, habit formation, the stream of consciousness, the self, attention, association, the perception of time, memory, sensation, imagination, perception, reasoning, voluntary movement, instinct, the emotions, will, and hypnotism. His other classic psychological work, The Varieties of Religious Experience (1902), explored the relationships between religious experience and psychology.

Jenkins, James J. (b. 1929, St. Louis; Ph.D., Psychology, Minnesota, 1950). Jenkins spent most of his career in the Department of Psychology and the Center for Research on Human Learning at Minnesota before moving to the University of South Florida. Focusing his research on language processing, Jenkins was prominent of those of his generation who made the transition from behaviorism to information processing.

Johnson-Laird, Philip N. (b. 1936, Yorkshire, England; Ph.D., Psychology, University College, London, 1967). After positions at Sussex and the MRC Applied Psychology Unit, Cambridge, Johnson-Laird became professor of psychology at Princeton University in 1989. His extensive research on language processing and reasoning, especially the use of mental models, is reported in Language and Perception (1976), Mental Models: Towards a Cognitive Science of Language, Inference, and Consciousness (1983), The Computer and the Mind : an Introduction to Cognitive Science (1988), Deduction (1991), and Human and Machine Thinking (1993).

Just, Marcel (b. 1947, Salisbury, England; Ph.D., Psychology, Stanford, 1972). Currently, Just works in the Center for Cognitive Brain Imaging at Carnegie Mellon University, where his research, often done in collaboration with Gail Carpenter, addresses such topics as sentence and text comprehension, coordinated comprehension of text and diagrams, and the role of working memory in comprehension and problem-solving, mental kinematics and mental models of dynamic events.

Kahneman, Daniel (b. 1934, Tel Aviv, Israel; Ph.D., Psychology, University of California, Berkeley, 1961). After appointments at the University of British Columbia and the University of California at Berkeley, in 1993 Kahneman moved to Princeton University, where he has appointments in the department of psychology and the Woodrow Wilson School of Public Affairs. His research focuses on human judgment and decision making; in research done collaboratively with Amos Tversky, Kahneman attempted to show that human reasoning does not follow strict normative principles. Rather, people rely on heuristics that simplify the problem, but sometimes lead to error. Many of the major results of this research were published in Judgment Under Uncertainty: Heuristics and Biases (1982). More recently Kahneman's interests have turned to the social and affective determinants of belief and choice.

Karmiloff-Smith, Annette (Ph.D., Psychologie Génétique et Expérimentale, Université de Genève 1977). Since 1982 Karmiloff-Smith has been a senior scientist at the MRC Cognitive Development Unit, London; her research focuses on cognitive development where she has focused on the cognitive restructuring that occurs during development. Her books include Beyond modularity : a developmental perspective on cognitive science (1991), Baby It's You: A unique insight into the first three years of the developing baby (1994), and Rethinking innateness (1996).

Katz, Jerrold J. (1932, Washington, DC; Ph.D., Philosophy, Princeton, 1962) Katz, whose research focuses on semantics, the philosophy of language, and the foundations of linguistics, is professor of linguistics and philosophy at the Graduate Center of the City University of New York. With Jerry Fodor, he sketched The structure of semantic theory in generative grammar in 1963. Later he defended a Platonist view of language, treating it as an abstract structure which can be analyzed in the same manner as mathematical systems. His books include The Philosophy of Language (1966), Semantic Theory (1972), Language and Other Abstract Objects (1981), and The Metaphysics of Meaning (1990).

Kay, Paul (b. 1934, New York, NY; Ph.D., Social Anthropology, Harvard, 1963). Kay has spent his academic career at the University of California at Berkeley, first in anthropology, and since 1982 in linguistics. Together with Brent Berlin, Kay conducted seminal research on color terms that resulted in Basic Color Terms (1969).

Kintsch, Walter (b. 1932, Temschwar, Romania; Ph.D., Psychology, University of Kansas, 1960). Since 1968, Kintsch has been on the psychology faculty at the University of Colorado in Boulder, where he is currently Director of the Institute of Cognitive Science. Kintsch's primary interests are discourse, text comprehension, and meaning representation. His construction-integration model of text comprehension combines a construction process, in which a textbase is constructed from the linguistic input as well as from the comprehender's knowledge base, with an integration phase, in which this textbase is integrated into a coherent whole. Kintsch is a past editor of the Psychological Review and the Journal of Verbal Learning and Verbal Behavior; his books include Learning, Memory, and Conceptual Processes (1970) and The Representation of Meaning in Memory (1974).

Koffka, Kurt (b.1886, Berlin, Germany, d. 1941, Northampton, MA; Ph.D., Psychology, University of Berlin, 1909). Koffka taught at the University of Giessen until 1927, when he moved to Smith College. Along with Wertheimer and Köhler, he was one of the founders of the Gestalt school of psychology and of its organ, the journal Psychologische Forschung. During his years at Giessen, Koffka wrote The Growth of the Mind (1927), in which he applied Gestalt notions to the problems of developmental psychology. Koffka did much to make Gestalt psychology more familiar to North Americans, especially through a long series of papers in the Psychological Bulletin in 1922. His later book, the Principles of Gestalt Psychology (1935), presented Gestalt psychology as complete theory of behavior.

Köhler, Wolfgang (b. 1887, Revel, Estonia, d. 1967, Enfield, NH; Ph.D., Psychology, University of Berlin, 1909). Köhler taught at the University of Berlin until 1935 and then at Swarthmore College until 1955. Along with Wertheimer and Koffka, Köhler was one of the founders of the Gestalt school of psychology and of its organ, the journal Psychologische Forschung. Köhler wrote several books presenting aspects of the Gestalt school of psychology: Gestalt Psychology (1929), The Place of Value in a World of Facts (1938), and Dynamics in Psychology (1940). One of Köhler=s major contributions was his work in the Canary Islands during World War I, where he demonstrated the perception of and response to relationships (rather than absolute stimulus values) in chicks (later known as transposition). There he also studied insight learning (closure over psychological gaps) in chimpanzees, as reported in The Mentality of Apes (1924). In his Die physischen Gestalten in Ruhe und im stationären Zustand (1920), Köhler argued that there is a correspondence in form between physical events in the brain and the subjective events caused by them.

Kolodner, Janet L. (Ph.D., Computer Science, Yale, 1980). Kolodner has spent her career at the at the Georgia Institute of Technology, where she is professor of computer science and Director of the EduTech Institute. Her research work investigates issues in learning, memory, and problem solving, utilizing the case-based reasoning approach in which, in reasoning the results of previous cases are applied to new situations. She is editor of The Journal of the Learning Sciences; her books include Case-Based Reasoning (1993).

Kosslyn, Stephen M. (b. 1948, Santa Monica, CA; Ph.D., Psychology, Stanford University, 1974) Kosslyn taught at Johns Hopkins, Harvard, and Brandeis Universities before moving to Harvard as Professor of Psychology in 1983. His work focuses on the nature of visual mental imagery and high-level vision; Kosslyn has defended a depictive as opposed to a propositional account of representations in perception and mental imagery. His earlier work employed primary the tools of cognitive psychology, but more recently he has used tools from neuroscience in the attempt to demonstrate the role of topographical mapped areas of the primate cortex in both visual perception and imagery. His books include Image and Mind (1980), Ghosts in the Mind's Machine (1983), Wet Mind: The New Cognitive Neuroscience (1992), and Image and Brain: The Resolution of the Image Debate (1994).

Kuhn, Thomas (b. 1922, Cincinnati, Ohio, d. 1996, Cambridge, Massachusetts; Ph.D., Physics, Harvard, 1949). Most of Kuhn's career was spent in history of science at Harvard, Princeton, and MIT. His 1962 contribution to the Encyclopedia of Unified Science, also published separately as The Structure of Scientific Revolutions, posed a major challenge to the conception of unified science with which the editors of the series were working. Kuhn argued that scientific change often occurred not through integration of theories into broader theories, but through revolutions that would radically alter the prevailing paradigm that guided scientific research in a field. In advancing this view Kuhn appealed both to work in Gestalt psychology and Jerome Bruner's work on perception. Kuhn also challenged traditional views of the ordinary practice of science, arguing that during eras of normal science scientists were not testing theoretical perspectives, but trying to fit nature into an already accepted paradigm.

Lakoff, George (b.1941, Bayonne, NJ; Ph.D., Linguistics, Indiana University, 1966). Beginning his career at the University of Michigan, Lakoff has been in the Linguistics Department at the University of California at Berkeley since 1972. He was one of the founders and developers of the generative semantics movement of the 1960s; and more recently has played the same role for cognitive linguistics. In collaborative work with Mark Johnson, he has focused on the role of metaphors in structuring our conceptual system; this collaboration resulted in Metaphors We Live By (1980). More recently he has published Women, Fire, and Dangerous Things: What Categories Reveal about the Mind (1987), and Moral Politics: What Conservatives Know That Liberals Don=t (1996).

Langacker, Ronald (b. 1942, Fond du Lac, WI; Ph.D., Linguistics, University of Illinois, 1966). Langacker, who has spent his career in the linguistics department at UCSD, is a major contributor to the development of cognitive linguistics. He has rejected the idea of autonomous syntax and instead advocated the view that syntactic structures arise from cognition, especially spatial cognition. His major works include Foundations of Cognitive Grammar, (Vol. 1, 1987, Vol. 2, 1991) and Concept, Image, and Symbol: The Cognitive Basis of Grammar (1991).

Lashley, Karl (b. 1890, Davis, WV, d. 1958, Poitiers, France; Ph.D., Genetics, Johns Hopkins University, 1914). Lashley=s career involved positions at the University of Minnesota, the University of Chicago, Harvard University, and Yerkes Laboratory of Primate Biology. Lashley was an ardent opponent of claims to cerebral localization of cognitive functions. In 1929 he published Brain Mechanisms and Intelligence, an account of his work on the effects of brain lesions on learning, memory, and discrimination in rat. He showed that the rate and accuracy of learning is proportionate to the amount of brain tissue available (the law of mass action), but that it is independent of the particular tissue that is available (the principle of equipotentiality).

Lenneberg, Eric H. (b. 1921, Düsseldorf, Germany, d. 1975, Ithaca, New York; Ph.D., Linguistics and Psychology, 1955). Working at Children=s Hospital Medical Center in Boston and at Cornell University, Lenneberg was an early proponent of a biological approach to language. He argued that language is the manifestation of species-specific cognitive propensities and that there is a critical period for language acquisition. He used data from a variety of impaired populations to gain general insights into language processing. He is the author of the landmark volume, Biological Foundations of Language (1967).

Levelt, Willem J. M. (b. 1938, Amsterdam; Ph.D., Psychology, Leiden, 1965). Levelt is Chair of Experimental Psychology at Nijmegen University and the founding director of the Max Planck Institute for Psycholinguistics in Nijmegen, one of the foremost centers for psycholinguistic research. His early research focused on perception, both visual and auditory, while his subsequent research has focused in psycholinguistics, including language production. Among his books is Speaking : From Intention to Articulation (1989).

Loftus, Elizabeth F. (b. 1944). In the department of psychology at the University of Washington, Loftus has focused her research on the accuracy of memory and the ways in which false memories may be induced, including in the course of legal investigations. Among her books are Eyewitness testimony (1979), Memory, surprising new insights into how we remember and why we forget (1980), and The myth of repressed memory: false memories and allegations of sexual abuse (1994).

Luria, Alexander Romanovich (b. 1902, Kazan, d. 1977, Moscow; Dr. of Pedagogical Sciences, Psychology, Moscow University, 1936 and M.D., Moscow University, 1943). Luria spent most of his career at Moscow University, where he headed the Department of Neuropsychology. He was strongly influenced by and collaborated with Vygotsky on studies of mental functioning in aphasia, and continued to work on brain organization, brain processes, and speech functions after Vygotsky's death. Luria postulated that the higher cortical functions are carried out through the interaction among cortical areas that work in a more general way but become associated through concrete activity and language. A founder of the field of neuropsychology, Luria developed a diagnostic system called syndrome analysis.  His earliest book on aphasia is Traumatic Aphasia (1947); later works include Higher Cortical Functions in Man (1962), The Mind of a Mnemonist (1968), An Introduction to Neuropsychology (1973), The Neuropsychology of Memory (1976) and The Making of Mind (1979).

MacWhinney, Brian (b. 1945, New York, NY; Ph.D., Psycholingusitics, University of California, Berkeley, 1974). After a period at the University of Denver, MacWhinney moved to the psychology department at Carnegie Mellon University in 1981. His research focuses on language acquisition, especially modeling the processes by which toddlers acquire language through a series of competitions between lexical items, phonological forms, and syntactic patterns. He is the director of CHILDES (Child Language Data Exchange System), which includes a large data base of transcripts of children's language use, and author of The acquisition of morphophonology (1978).

Mandler, George (b. 1924, Vienna, Austria; Ph.D., Psychology, Yale, 1953). Mandler founded the Department of Psychology at UCSD in 1965, and has spent the rest of his career there. In his memory he emphasized organization in memory and later the distinction between activation and elaboration. He also developed a discrepancy-evaluation theory of emotion and has developed phenomenal and theoretical analyses of consciousness. Mandler edited Psychological Review from 1970 to 1976. His books include The Language of Psychology (1959), Mind and Emotion (1975), Cognitive Psychology: An Essay in Cognitive Science (1985), and Human Nature Explored: Psychology, Evolution, Society (1997).

Marr, David (b. 1945, Woodford, England, d. 1980) Trained in psychology, Marr held research fellowships at Trinity College and King's College, Cambridge, before moving to MIT, where he was a member of the AI Lab from 1973 until his death in 1980. In his early work, Marr developed computational models of a number of neural systems, including the cerebellum and the hippocampus. His major contribution, though, concerned computational models of visual processes, including the extraction of lines from retinal images, the determination of depth and motion, and the representation of objects to facilitate recognition. His book, Vision: A Computational Investigation into the Human Representation and Processing of Visual Information, was published posthumously in 1982 and is still influential.

McCarthy, John (b. 1927, Boston, MA; Ph.D., Mathematics, Princeton, 1951). McCarthy was a codirector of the Dartmouth conference in 1956 at which the term artificial intelligence was first employed; in 1958 he also invented the programming language LISP, which has been one of the most used languages in AI. After cofounding the MIT AI Laboratory with Marvin Minsky, in 1962 McCarthy moved to Stanford University, where he founded and directed the Artificial Intelligence Laboratory at Stanford. His main research contributions common sense knowledge and reasoning. Many of his papers are collected in Formalizing Common Sense (1991).

McClelland, James S. (b. 1948, Cambridge, MA; Ph.D., Cognitive Psychology,University of Pennsylvania, 1975). McClelland began his career at UCSD, moving to Carnegie-Mellon University in 1984. Together with David Rumelhart, he established the the PDP research group at UCSD, which played a major role in re-introducing connectionist or neural network modeling in cognitive science in the 1980s, especially through the publication of Parallel Distributed Processing: Explorations in the Microstructure of Cognition (two volume, 1986). In more recent research, McClelland has continued to develop connectionist models of language processing and of brain deficits.

McKoon, Gail (b. 1948, Iowa; Ph.D., Psychology, University of Colorado, 1976). McKoon is professor of psychology at Northwestern University. Her research interests lie in psycholinguistics, including text processing, syntactic contributions to meaning, and discourse models; memory, including retrieval processes, models of implicit versus explict tasks, and competitive model testing.

McCulloch, Warren S. (b. 1898, Orange, NJ, d. 1969; M.D., Columbia, 1927). McCulloch was director of the Neuropsychiatric Institute at the University of Illinois from 1941 to 1952, when he moved to the Research Laboratory of Electronics at MIT. While at the Neuropsychiatric Institute he began a collaboration with a young logician, Walter Pitts, that resulted in some of the first neural network models of mental processes. At MIT McCulloch and Pitts established a fruitful collaboration with Jerry Y. Lettvin and Humberto R. Maturna. Their investigation of feature detectors in the frog=s retina resulted in the classic paper, What the frog's eye tells the frog's brain. McCulloch's interest in neural networks extended to questions of distributed control and reliable performance from unreliable parts; many of his influential papers were published in Embodiments of Mind (1965).

Medin, Douglas (b. 1944, Estherville, Iowa; Ph. D., Psychology, University of South Dakota, 1968). After a number of years at the University of Illinois, Medin is currently at Northwestern University. He has been a major contributor to research on concepts and categorization; his 1981 book with Edward Smith, Categories and concepts, is an analysis of different models of categorization. His current work focuses on the role of expertise and culture in the conceptual organization of biological categories.

Miller, George A. (b. 1920, Charleston, WV; Ph.D., Experimental Psychology, Harvard, 1946). Miller spent most of his career until 1958 at Harvard, where he played a pioneering role in the development of psycholinguistics and cognitive psychology and codirected the Center for Cognitive Studies with Jerome Bruner. His 1960 book with Eugene Galanter, and Karl Pribram, Plans and the Structure of Behavior, was a pioneering work in modeling information structures in the mind. After leaving Harvard, Miller went first to Rockefeller, and then to Princeton University, where he has remained since. Much of his recent research has been directed at the semantics of individual words, which he explored with Johnson-Laird in Language and Perception (1976) and more recently modeled in a large computer program called WordNet. Among his books are The Psychology of Communication (1967), Language and Speech (1981), and The Science of Words (1991).

Milner, Brenda (b. 1915, Manchester, England; Ph.D., Psychology, McGill, 1952). Milner has spent her career McGill University, where she is professor of psychology in the Department of Neurology and Neurosurgery and at the Montreal Neurological Institute. Her initial research focused on the effects of temporal lobe damage in humans, especially the consequences for memory. She performed the initial neuropsychological examinations of the memory losses in H.M., who had parts of both temporal lobes removed in 1953 and has since become one of the most widely studied amnesic patients. Milner's research has extended to the cognitive deficits following damage to other brain areas, especially frontal cortex.

Minsky, Marvin (b.1927, New York City; Ph.D., Mathematics, Princeton, 1954). Minsky has spent his professional career at MIT, where he cofounded the Artificial Intelligence Laboratory with John McCarthy. He edited one of the first books on artificial intelligence, Semantic Information Processing (1968), in which most of the chapters were based on his students' Ph.D. dissertations. Minsky's research continued to generate both theoretical and practical advances in artificial intelligence, especially in the areas of knowledge representation, computational semantics, machine perception, and learning. In 1969 he and Seymour Papert published an influential book, Perceptrons, which contained a generally negative assessment of the potential for neural networks. Thereafter, Minsky=s notion of a >frame= played a major role in the search for higher level knowledge representations in AI. In 1985 he published The Society of Mind, proposing a theory of mind that he had been developing throughout the 1970s and 1980s. In his view, intelligence is not the product of any singular mechanism, but comes from the managed interaction of a diverse variety of resourceful agents. Minsky was also one of the pioneers of intelligence-based mechanical robotics, designing and building some of the first mechanical hands with tactile sensors, visual scanners, and their software and computer interfaces.

Mishkin, Mortimer (b. 1926, Fitchburg, Mass.; Ph.D., Psychology, McGill, 1951). Mishkin has spent his career at the National Institutes of Mental Health, where he is currently Chief of the Laboratory of Neuropsychology. Much of Mishkin's research has been devoted to studying neural pathways involved in perception and attention, recognition and recall, emotion and motivation, and volition and movement, as well as brain mechanisms of learning. In the early 1980s he, together with Leslie Ungerleider, developed an influential model of visual processing in which separate pathways were responsible for identifying and locating objects (the what and where pathways).

Nagel, Thomas (Ph.D., Philosophy, Harvard). Nagel's career has been spent at New York University, where he is current professor of both philosophy and law. By asking the question, What is it like to be a bat? Nagel has inspired much of the recent philosophical theorizing about consciousness. His books include The View From Nowhere (Oxford, 1986), Other Minds (1995), and The Last Word (1997).

Neisser, Ulric (b. 1928, Kiel, Germany; Ph.D., Psychology, Harvard, 1956). Neisser career has included appointments at Brandeis, Pennsylvania, Cornell, and Emory, where he founded the Emory Cognition Project and edited a number of volumes based on its conferences. In 1996 he returned to Cornell. Neisser is best known for three books: Cognitive Psychology (1967), which helped to establish that field, Cognition and Reality (1976), which attempted to reorient it with an infusion of ecological psychology, and Memory Observed: Remembering in Natural Contexts (1982), an edited book which introduced the ecological approach to the study of memory. Other research areas in which he has had an impact include divided attention and the effects of mental practice. Recently he has focused on characterizing several aspects of the self and self-knowledge (the ecological, interpersonal, remembered, private, and conceptual selves).

Newell, Allen (b. 1927, San Francisco, d. 1992, Pittsburgh; Ph.D., Industrial Administration, Carnegie Institute of Technology, 1957). Newell was a scientific staff member at Rand Corporation when he met and began a collaboration with Herbert Simon; together they worked on computer simulations of cognitive processes such as chess playing and problem solving and developed the production system architecture that is widely used in AI. Newell joined Simon at Carnegie Institute of Technology (now Carnegie-Mellon University), where he earned his Ph.D. and remained on the faculty for the rest of his career. Their work on problem solving and production systems culminated in Human Problem Solving (1972). With Simon, he also proposed the Physical Symbol System hypothesis, according to which the mind is defined as a system operating on physical symbols. Much of his later work centered on SOAR, an architecture for intelligent problem solving and learning that emphasizes chunking as a strategy. In Unified Theories of Cognition (1990) Newell argued for the importance of developing architectures capable of performing all cognitive tasks, and argued that SOAR provided such an architecture.

Newsome, William T. (Ph.D., Biology, Caltech, 1980). Newsome has been in the department of neurobiology at Stanford since 1988, where his research, employing single neuron recording experiments with primates, focuses on the neural mechanisms underlying visual perception and visually guided behavior.

Nisbett, Richard (b. 1941, Littlefield, TX; Ph.D., Psychology, Columbia, 1966). Nisbett has been at Michigan since 1971, where his research is focused on social psychology and on the relations between social and cognitive psychology. With Lee Ross, he wrote Human Inference Strategies and Shortcomings of Social Judgment (1980) in which they attempted to demonstrate that judgment errors are due to extending beyond their proper domain the same heuristics as account for successful human reasoning. In work with Timothy Wilson, Nisbett showed that people are often confabulate about their reasons for action. His collaboration with John Holland, Keith Holyoak, and Paul Thagard resulted in Induction: Processes of Inference, Learning, and Discovery (1986), which attempted to integrate a descriptive and normative analysis of human inductive inference.

Norman, Donald A. (b. 1935, New York, NY; Ph.D., Mathematical Psychology, University of Pennsylvania, 1962). After spending 1962-1966 at the Center for Cognitive Studies at Harvard, Norman spent most of his academic career at UCSD before joining Apple Corporation and then Hewlett Packard in the 1990s. While in the psychology department at UCSD he collaborated with Peter Lindsay on Human Information Processing (1972) and with David Rumelhart and the LNR Research Group on Explorations in Cognition (1975). He and Rumelhart established the Institute for Cognitive Science at UCSD and, when it became a department in 1988, Norman was its first chair. Initially known for his mathematical and computer simulation models of memory and cognition, Norman later focused on how cognition is distributed across people and the tools they construct and how tools and other artifacts can be better designed for use by humans. This work resulted in The Design of Everyday Things (1990), and Things that Make Us Smart (1993).

Palmer, Steve (b. 1948, Plainfield, NJ; Ph.D., Psychology, University of California, San Diego, 1975). Palmer has been in the Psychology Department at the University of California, Berkeley, throughout his professional career. His field of specialization is visual perception, where he takes an information processing approach, while integrating Gestalt insights with connectionist modelling to account for the fluid, flexible, and context-sensitive aspects of human cognition.

Papert, Seymour (b.1928, South Africa). Papert pursued mathematical research at Cambridge University from 1954-1958 and then worked with Jean Piaget at the University of Geneva from 1958-1963. Since 1963 he has been at MIT, where he became co-director of the AI Laboratory, and is now Lego Professor of Learning Research. At MIT he collaborated with Marvin Minsky on Perceptrons (1969), which temporary helped reduce interest in neural networks and fostered increased pursuit of symbolic models. Much of his work has been directed to the use of computers and computer programming in education; he developed the Logo language, with which children can write programs to control the moments of mechanical turtles or perform other tasks. Among his books are Mindstorms: Children Computers and Powerful Ideas (1980), The Children's Machine: Rethinking School in the Age of the Computer (1992), and The Connected Family: Bridging the Digital Generation Gap (1996).

Penfield, Wilder (b. 1891, Spokane, WA, d. 1976, Montreal, Canada; M. D., Johns Hopkins University, 1918). Penfield taught at McGill from 1928 until 1960, where he founded the Montreal Neurological Institute, which he directed from 1934 to 1960. As a brain surgeon, Penfield specialized in the treatment of epileptics by removing portions of cortex. In order to determine which areas of cortex could not safely be removed, Penfield employed electrical stimulation, discovering that stimulation of certain parts of the cortex in human subjects can evoke vivid memories of past life experiences. Penfield presented the results of his research in a number of volumes: Epilepsy and Cerebral Localization (1941), The Cerebral Cortex of Man (1950), The Excitable Cortex in Conscious Man (1958), Speech and Brain Mechanisms (1959), and The Mystery of the Mind. (1975).

Petersen, Steven (b. 1952, Alameda, CA; Ph. D., Biology, California Institute of Technology, 1982). Petersen has spent his academic career at Washington University School of Medicine, where he has engaged in a productive collaboration with Marcus Raichle and numerous other collaborators and has played a major role in developing positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) as tools for imaging functionally active areas in the brain. His imaging work has focused on tasks involving language processing and memory and he has explored the changes in brain mechanisms involved in novice and practiced behavior.

Piaget, Jean (b. 1896, Neuchatel, Switzerland, d. 1980, Geneva, Switzerland; Ph.D., Biology, University of Neuchatel, 1918). Piaget spent most of his career at the University of Geneva, where he was professor of child psychology and history of scientific thought from 1929 to 1971; he also founded and directed until his death the International Center of Genetic Epistemology in Geneva. Drawing upon detailed longitudinal observation of his own three children's early development as well as analysis of older children's responses to ingenious tasks he devised, Piaget formulated a constructivist theory of development that emphasizes the interaction of nature and nurture via the child's own actions. He is best known for positing stages of development that the child traverses through processes of assimilation, accommodation and equilibration, but these are just the most accessible parts of an ambitious theory that combined mathematical, biological and philosophical considerations. Among the most influential of his dozens of books are The Language and Thought of the Child (1926), The Origins of Intelligence in Children (1952), The Growth of Logical Thinking from Childhood to Adolescence (1958), and The Principles of Genetic Epistemology (1972).

Pinker, Steven (b. 1954, Montreal, Canada; Ph.D., experimental psychology, Harvard, 1979). Pinker has been at MIT since 1982, where he is currently a professor in the Department of Brain and Cognitive Studies and director of its McDonnell-Pew Center for Cognitive Neuroscience. Strongly influenced by Chomsky, Pinker's research in the psychology of language has argued for an innate neural system employing a discrete combinatorial code, or grammar dedicated to language. Unlike Chomsky, Pinker views this system as a adaptation promoted by natural selection. Pinker also does work in visual perception and is the author of Language Learnability and Language Development (1984), Learnability and Cognition (1989), The Language Instinct (1994) and How the Mind Works (1997).

Posner, Michael I. (b. 1936, Cincinnati, OH; Ph.D., Psychology, University of Michigan, 1962). Posner has been a Professor of Psychology at the University of Oregon since 1965. During the 1960s and 1970s, his work relied primarily on chronometric methods to identify component cognitive systems; the results are presented in Chronometric Explorations of Mind (1978). Subsequently, Posner began to draw more on neuroscience tools. From 1985 to 1988 he joined Marcus Raichle and Steven Petersen at Washington University, where they developed PET methods appropriate to imaging brain functions; many of these results are presented in Images of Mind (1994). Since 1988, Posner has been working on relating tools for identifying spatial locations involved in cognitive performance (PET and fMRI imagining) and tools for identifying the time of their involvement (ERP), with a particular focus on the plasticity of human attention and skill acquisition.

Premack, David (b. 1925, Aberdeen, SD; Ph.D., Experimental Psychology, University of Minnesota, 1955). Much of Premack's career was spent at the University of Pennsylvania before he moved to Ecole Pratique des Hautes Etudes, Paris. In a notable project in the 1970s, Premack taught a chimpanzee, Sarah, a linguistic system employing plastic blocks. His books include Intelligence in Man and Ape (1976), and The Mind of an Ape (1983).

Pribram, Karl H. (b. 1919, Vienna; M. D., University of Chicago, 1941). Pribram spent much of his career at Yale and Stanford; he is now Director of the Center for Brain Research at Radford University. His research efforts have been devoted to identifying nervous system substrates of primate behavior and determining the role of neocortex in emotion and cognition. Pribram collaborated with George Miller and Eugene Galanter on Plans and the Structure of Behavior (1960), which introduced TOTE units as an alternative to reflex arcs and providing cognitive structure to cognition. He is best known for his proposed holographic modeling of memory. His books include Languages of the Brain (1971), What makes us Human (1971), and Brain and perception: Holonomy and Structure in Figural Processing (1991).

Putnam, Hilary (b. 1926, Chicago; Ph.D., Philosophy, UCLA, 1951). After teaching at Northwestern University, Princeton University, and MIT, Putnam moved to Harvard in 1976. Drawing on the theory of recursive functions and Turing machines, Putnam formulated a stance on the mind-body problem that he named 'functionalism' in the 1950s, according to which it is organization, not material composition, that is relevant to the study of cognition. Putnam now believes that different computational (Turing machine) states can realize the same mental state, and thus that the mind cannot be identified with any particular computing machine. Putnam's work can be found in Philosophical Papers (3 vols., 1975-83), Representation and Reality (1988), and Pragmatism: An open question (1995).

Pylyshyn, Zenon W. (1937, Montreal; Ph.D., Experimental Psychology, University of Saskatchewan, 1963). After spending much of his career at Western Ontario University, Pylyshyn moved to Rutgers University in 1994, where he is professor of psychology and Director of the Center for Cognitive Science. One of Pylyshyn's major interests, developed in Computation and Cognition: Toward a Foundation for Cognitive Science (1984), has been in determining the nature of the human cognitive architecture, the level of organization at which the basic cognitive capacities are specified. Pylyshyn has also been a major critic of analog accounts of mental imagery and of connectionist models of cognition. In his research on visual attention, he has developed models of how the visual system tracks targets which it has already examined.

Quillian, M. Ross (b. 1931, Los Angeles; Ph.D., Psychology, Carnegie-Mellon, 1968). Quillian's career has been spent at the University of California, Irvine in social science and then political science. His major contribution to cognitive science was the development of semantic networks, in which concepts are represented as nodes linked to other nodes.

Raichle, Marcus (b. 1937, Hoquiam, WA; M. D., University of Washington, Seattle, 1964). Raichle has been at the Washington University School of Medicine since 1971, where he has been a leader in the development of brain imaging techniques and their application to cognitive function. He played a pivotal role in the development and application of positron emission tomography (PET), which was invented in Mike Ter-Pogossian's laboratory at Washington University in the early 1970s; he is now concentrating on fMRI. With Michael Posner, he published Images of Mind (1994), which provides an accessible overview of brain imaging research.

Reber, Arthur (b. 1940, Philadelphia; Ph.D. Psychology, Brown, 1967). Since 1970, Reber has been in psychology at Brooklyn College, where much of his research has addressed implicit memory. His books include The Penguin dictionary of psychology (1985) andImplicit learning and tacit knowledge : an essay on the cognitive unconscious (1993).

Rips, Lance J. (b. 1947, Omaha, Nebraska; Ph.D., Psychology, Stanford, 1974). After nearly 20 years at the University of Chicago, Rips moved to Northwestern University in 1993. The major focus of his research is reasoning, especially dedeuctive inference; much of his research is presented in The psychology of proof: Deductive reasoning in human thinking (1994).

Roediger, Henry L. (Ph.D., Psychology, Yale, 1973). After appointments at Purdue and Rice Universities, Roediger is now in the department of psychology at Washington Universisty in St. Louis. His research has been in the field of memory, most recently on the phenomenon of false memory.

Rosch, Eleanor (Ph.D., Psychology, Harvard). Rosch, who has spent her career at the University of California, Berkeley, was a major instigator of contemporary research on concepts and categorization. She found that concepts such as bird exhibited a graded structure from more prototypical to less prototypical instances, and that a number of psychological measures, such as response time to evaluate whether an instance is a member of a category, correlated with the prototypicality of the instances. Much of this research is presented in Cognition and Categorization (1978). More recently, her interests have moved to eastern psychologies and psychology of religion, as manifested in The Embodied Mind: Cognitive Science and Human Experience (1991).

Rosenblatt, Frank (b. 1928, New Rochelle, New York, d. 1971, Easton, Maryland; Ph.D., Psychology, Cornell, 1956). Rosenblatt began his career at the Cornell Aeronautical Laboratory in Buffalo before returning to the main campus of Cornell in Ithaca as director of the Cognitive Systems Research Program. His main contribution was the development of a perceptron, a neural network system that learned to identify such objects as letters. He presented his work on perceptrons in his book Principles of Neurodynamics (1962). Rosenblatt also explored the possibility of transferring learning behavior from trained to naive rats by injecting brain extracts from the former into the latter.

Rumelhart, David (b. 1942, Wessington Springs, SD; Ph.D., Mathematical Psychology, Stanford, 1967). Rumelhart was in psychology at UCSD from 1967 to 1987, when he moved to Stanford. While at UCSD he began a fruitful collaboration with Donald Norman and the LNR research group, resulting in Explorations in cognition (1975). A subsequent collaboration with James McClelland and the PDP research group produced Parallel Distributed Processing: Explorations in the Microstructure of Cognition (2 vols., 1986), which played a major role in re-introducing connectionist models into cognitive science. With Hinton and Williams, Rumelhart discovered the technique of back-propagation for learning in multilayered nets. Since moving to Stanford, Rumelhart has concentrated on the development of neurally inspired computational architectures.

Schacter, Daniel L. (b. 1952, Brooklyn, NY, Ph.D., Psychology, Toronto, 1981). After positions at Toronto and Arizona, Schachter moved to Harvard in 1991. Much of his research has focused on implicit memory, memory that results in facilitated performance on tasks in the absence of concious recollection by the subject. His books include Stranger behind the engram: Theories of memory and the psychology of science (1982) and Searching for memory: The brain, the mind, and the past (1996).

Schank, Roger (b.1946, New York, NY; Ph.D., Linguistics, University of Texas, 1969). After appointments at Stanford and Yale, Schank is now director of the Institute for the Learning Sciences (ILS) at Northwestern University and President of the Learning Sciences Corporation. Beginning his career by building AI systems for natural language processing, Schank then collaborated with Robert Abelson on Scripts, Plans, Goals, and Understanding (1977), in which they developed the idea of scripts as higher-level knowledge structures. Schank extended this research into memory structures in Dynamic Memory (1982). His more recent work stresses the value of learning from experts, developing skills rather than perfecting routines, and applying the benefits of >just-in-time= training; this research is presented in Engines for Education (1995).

Searle, John R. (b. 1932, Denver; D. Phil., Philosophy, Oxford, 1959). Since 1959, Searle has been in the Department of Philosophy at the University of California, Berkeley. Much of Searle's early research was in the philosophy of language and focused on speech acts, culminating in Speech Acts (1969). More recently he has become a critic of what he terms strong artificial intelligence, according to which all there is to having a mind is implementing the right computer program. His major argument, the Chinese Room argument, was first presented in a 1980 Behavioral and Brain Sciences article, Minds, Brains, and Programs. Searle's most recent books include Intentionality: An Essay in the Philosophy of Mind (1983), and The Rediscovery of the Mind (1992).

Selfridge, Oliver G. From 1951 to 1975 Selfridge was with the Lincoln Laboratory at MIT. He then moved to Bolt Beranek and Newman as Senior Scientist; in 1983 he moved again to GTE Laboratories as Chief Scientist in the Computer and Information Systems Laboratory, from which he retired in 1993. Selfridge was one of the earliest investigators to explore neural networks, and in the 1950s developed the Pandemonium model of perceptual recognition in which a number of simple agents each tried to recognize their own target input and then competed to activate consistent decision units. Much of his subsequent research focused on machine learning.

Selz, Otto (b. 1881, Munich, d. 1943, Auschwitz; Ph.D., Psychology, University of Munich, 1909). Selz worked at the University of Bonn from 1912 to 1923 and at Handelshochschule in Mannheim from 1923 to 1933. A member of the Würzburg school of psychology, Selz studied the organized thinking process, stressing the notion that active processing takes place in the mind, and he called for a psychology of thinking that would be concerned with processes rather than content. His work was a major influence on the development of Herbert Simon's approach to studying human problem solving.

Shannon, Claude E. (b. 1916, Gaylord, MI; Ph.D., Mathematics, MIT, 1940). Shannon joined the staff of Bell Laboratories in 1941 to work on the problem of how to transmit information most efficiently; in the course of his research he developed an method for measuring information and became one of the pioneers of information theory, a full statement of which appeared in The Mathematical Theory of Communication (1949). From 1958 to 1980, Shannon taught at MIT.

Shepard, Roger N. (b. 1929, Palo Alto, CA; Ph.D., Psychology, Yale, 1955). After stints with ATT Bell Laboratories and Harvard, Shepard moved to Stanford in 1968 and has remained there since. Shepard is known both for his mathematical models of cognitive processes, especially his work on multlidimensional scaling, and for his research on mental rotation of geometric figures. His books include Mental Images and Their Transformation (1982) and Mind Sights (1990).

Sherington, Sir Charles Scott (b. 1857, London, UK, d. 1952, Eastbourne, UK; M. B., Cambridge, 1885). Sherington held numerous positions in pathology and physiology, including at the University of Liverpool from 1895 to 1913 and Oxford from 1913 until 1935. He received the Nobel prize in physiology and medicine in 1932. In the course of his research on reflex arcs he engaged in detailed neuroanatomy, which resulted in his discovery of gaps between neurons which he termed synapses. He studied reflexes as functional units operating not in isolation, but under control of higher levels of neural activity. His views on how reflexes were integrated into behavior were presented in The Integrative Action of the Nervous System (1906). His other books include The Brain and its Mechanism (1933) and Man on His Nature (1951).

Simon, Herbert A. (b. 1916, Milwaukee, WI; Ph.D.; Political Science, University of Chicago, 1943). Simon=s initial research focused on decision making in organizations, work for which he received the Nobel Prize in Economics in 1978. Simon's interested gradually turned to the psychology of problem solving and the use of computers to model this process. In the 1950s he began a collaboration with Allen Newell, with whom he developed the production system architecture that is widely used in AI and produced some of the earliest computational models of human reasoning. This work culminated in Human Problem Solving (1972). With Newell, he also proposed the Physical Symbol System hypothesis. In his more recent work, Simon has often focused on modeling scientific discovery. Among his many books are The Sciences of the Artificial (1969), Models of Discovery (1977), Models of Thought (Two Volumes, 1979, 1989) and Scientific Discovery (1987).

Smith, Edward E. (b. 1940, Brooklyn, NY; Ph.D., Experimental Psychology, University of Michigan, 1966). After positions at Wisconsin, Stanford, Bolt Beranek and Newman, Smith moved to the University of Michigan in 1986, where he directs the Cognitive Science and the Cognitive Neuroscience Program. Smith has worked in the areas of perception, memory, and text processing; some of his more important contributions have been in the study of categorization and reasoning. In 1981 he and Douglas Medin published Categories and Concepts. His most recent work employs neuroimaging to study visual-spatial working memory, problem-solving, and age-related changes in working memory.

Sperry, Roger W. (b. 1913, Hartford, Connecticut, d. 1994; Ph.D., Zoology, Chicago, 1941). Sperry, who spent most of his career at the California Institute of Technology, made extensive studies of patients in which the two hemispheres of the cortex were separated in the course of treatment for epilepsy. He received the Nobel Prize in 1981 for this research on hemispheric interactions and specialization. His books include Problems Outstanding in the Evolution of Brain Function (1964) and Science and Moral Priority (1983).

Squire, Larry R. (b. 1941, Cherokee, Iowa; Ph.D., Psychology, MIT, 1968). Squire has spent his career at the UCSD, where his research has addressed the anatomy, physiology, and function of memory. His research examines amnesias as well as nonconscious learning and memory. Some of this research is reported in Memory and Brain (1987).

Sternberg, Saul H. (b. 1933, New York City; Ph.D., Social Relations, Harvard, 1960). After a short period at the University of Pennsylvania, Sternberg moved to Bell Laboratories, where he chaired the Human Information-Processing Research Department from 1970 to 1985. He then returned to the University of Pennsylvania. Among his accomplishments, Sternberg developed an additive factors approach to analyzing reaction-time data and advanced a model of exhaustive search for memroy scanning tasks. His research has focused on such cognitive phenomena as visual processing, motor control, and perception of time.

Stevens, Stanley Smith (b. 1906, Ogden, UT, d. 1973, Vail, CO; Ph.D., Psychology, Harvard, 1933). Stevens' career was spent at Harvard where he established a psychophysics laboratory in which many of the founders of cognitive psychology began their careers. His major interest was in measurement and psychological scaling; among his contributions were the method of magnitude estimation and Stevens= law. In 1951 Stevens edited the Handbook of Experimental Psychology, which was rewritten in 1988 as Stevens' Handbook of Experimental Psychology.

Thagard, Paul (b.1950, Yorkton, Saskatchewan, Canada; Ph.D., Philosophy, University of Toronto, 1977). Currently, Thagard is Professor of Philosophy at the University of Waterloo, where his research has focused on the development of computational models of scientific reasoning. His books include Induction: Processes of inference, learning, and discovery (1986), Computational philosophy of science (1988), Conceptual Revolutions (1992), and Mental leaps: analogy in creative thought (MIT Press, 1995).

Titchener, Edward Bradford (b. 1867, Chichester, Sussex, England, d. 1927, Ithaca, NY; Ph.D., Psychology, Leipzig, 1892). A student of Wundt's who emphasized the introspectionist and structuralist aspects of his mentor=s work, Titchener spent his career at Cornell University. His most important book was Experimental Psychology (four volumes, 1901-5).

Tolman, Edward (b. 1886, West Newton, MA, d. 1959, Berkeley, CA; Ph.D., Psychology, Harvard, 1915). Tolman spent most of his career at the University of California, Berkeley, where he established a rat laboratory. To account for his rats= maze navigation and other abilities, Tolman posited such cognitive explanations as mental maps. Departing from standard behaviorism, he called his research program purposive behaviorism. His major work is Purposive Behavior in Animals and Men (1932).

Trabasso, Thomas (b. 1935; Ph.D., Experimental Psychology, Michigan State University, 1961). Currently, Trabasso is a cognitive psychologist at the University of Chicago. His research interests center on how people understand and construct narrative representations of everyday life and fiction. Trabasso is interested in individual and developmental differences in memory and comprehension of narratives, and how narrative understanding contributes to social interaction in conflict, argumentation, and emotional experience.

Tulving, Endel (b. 1927, Estonia; Ph.D., Experimental Psychology, Harvard, 1957). Currently, Tulving is Tanenbaum Chair in Cognitive Neuroscience at the Rotman Research Institute, University of Toronto; since 1996 he has also held a permanent visiting position at Washington University in St. Louis. Throughout his professional career, Tulving has studied human memory. Among the important concepts and distinctions he has introduced are cue-dependent forgetting, encoding specificity, episodic versus semantic memory, and availability versus accessibility of stored information. Most recently he has developed the HERA model of encoding/retrieval asymmetry of the frontal lobes. He is the author of Elements of Episodic Memory (1983).

Turing, Alan (b. 1912, London, UK, d. 1953, Wilmslow, Cheshire, UK; Ph.D., Mathematics, Princeton, 1938). Turing's academic career was spent at Cambridge and Manchester; during World War II he played a major role in British attempts at Bletchley Park to break German cryptographic codes. This research played a major role in developing basic ideas of the computer. In addition to the development of physical machines, Turing's contributions include the Turing machine (a framework for computing any decidable function) and the Turing test (for evaluating whether machines are thinking).

Tversky, Amos (b. 1937, Haifa, Israel, d. 1996, Stanford, CA; Ph.D., Psychology, Michigan, 1965). Tversky spent much of his career at Stanford University, where his research focused on similarity and scaling (including nearest neighbor analysis) and on human judgment and decision making. In research done collaboratively with Daniel Kahneman, Tversky marshalled evidence that human reasoning does not follow strict normative principles. Rather, people rely on heuristics that simplify the problem, but sometimes lead to error. Many of the major results of this research were published in Judgment Under Uncertainty: Heuristics and Biases (1982).

Van Essen, David (b. 1945, California; Ph. D., Neurobiology, Harvard, 1971). van Essen spent from 1976 to 1992 at the California Institute of Technology before moving to Washington University Medical School as Director of the McDonnell Center for Higher Brain Function. van Essen's research has focused on the functional organization of visual cortex employing anatomical, physiological, and computational approaches.

van Gelder, Timothy (b. 1962, Darwin, NT, Australia; Ph. D., Philosophy, University of Pittsburgh, 1989). van Gelder holds appointments in philosophy at Indiana University and the University of Melbourne, Australia. His early research focused on the nature of representation in connectionist systems; more recently he has explored how cognition might best be analyzed in terms of dynamical systems models which forego both computation and representation. His 1995 book, Mind as Motion: Explorations in the Dynamics of Cognition, edited with Robert Port, has played a major role in advancing the dynamical system approach in cognitive science.

von Helmholtz, Hermann (b. 1821, Potsdam, Germany, d. 1894, Berlin, Germany; M.D., Friedrich Wilhelm Medical Institute in Berlin, 1842). Helmholtz, who held positions at Königsberg, Bonn, and Heidelberg, was a major contributor to both physics and physiology. In Die Lehre von den Tonempfindungen(1863) and Handbuch der physiologischen Optik (1867), he defined the problems for the experimental psychology of visual and auditory perception for decades to follow. He articulated a conception of perception according to which it requires active, unconscious, automatic, logical inference on the part of the perceiver.

von Neumann, John (b. 1903 Budapest, Hungary, d. Washington, D.C., 1957; Ph.D., Mathematics, University of Budapest, 1926). After faculty appointments at Berlin, Hamburg, and Princeton, von Neumann spent the majority of his career at the Institute for Advanced Study at Princeton. He made many significant contributions to pure mathematics, quantum theory, the theory of electronic computing devices, and the theory of games. He played a major role in the development of computers and proposed the basic architecture of modern computers, which bears his name. His research on the theory of games, conducted in collaboration with Oskar Morgenstern, focused on the study of risky decision making and resulted in Theory of Games and Economic Behavior (1944).

Vygotsky, Lev Semyonovich (b. 1896, Orsha, Belorus, d. 1934, Moscow). Much of Vygotsky's career was spent at Moscow University=s Institute of Psychology. His approach to mind emphasized the role of social context in the development of individual minds. Well after his death, his work came to the attention of English speakers after the publication of Thought and Language (1962) and has achieved increasing influence in the 1990s.

Wernicke, Carl (b. 1848, Tarnowitz, Upper Silesia, d. 1905, Dörreberg-im-Geratal; M.D., University of Breslau, 1870). Wernicke practiced medicine in Berlin from 1875 to 1885 and then taught psychiatry at Breslau from 1885 to 1904. He is most famous for discovering a second form of aphasia in addition to that studied by Broca. In Wernicke=s aphasia, the ability to understand the meaning of spoken language is lost, while self-generated speech and the understanding of written language are preserved. Wernicke attributed the cause of this deficit to an area of the cerebral cortex that comprises parts of the first and second temporal gyri and the supramarginal angular gyrus, which has come to be be known as Wernicke's area.

Wertheimer, Max (b. 1880, Prague, Austria-Hungary, d. 1943, New Rochelle, NY; Ph.D., Psychology, University of Würzburg, 1904). Wertheimer held positions in Frankfurt and Berlin before moving to the New School for Social Research in1933, where he remained for ten years. In 1912, Wertheimer proposed an analysis of an apparent motion experiment according to which the perceived movement was a new phenomenon, a whole or Gestalt, that was not reducible to the elements that gave rise to it. This marked the beginning of the Gestalt school of psychology. He argued that it was the prior perception of the whole that determined how the parts would be perceived, not the other way around. Together with Koffka and Köhler, Wertheimer established a new journal, Psychologische Forschung, devoted to Gestalt ideas. Wertheimer=s later attempts to extend the idea of Gestalten to creative thinking were published posthumously in Productive Thinking (1945).

Wiener, Norbert (b. 1894, Columbia, MO, d. 1964, Stockholm, Sweden; Ph.D., Philosophy, Harvard University, 1913). Wiener remained at MIT from 1919 to 1960. He was a major contributor to the cybernetics movement, even naming it in his 1948 book, Cybernetics. He defined >cybernetics= as a discipline concerned with the comparative study of control mechanisms in the nervous system and computers. Among Wiener's other books are The Human use of Human Beings (1950) and Cybernetics of the Nervous System (1965).

Wiesel, Torsten (b. 1924, Uppsala, Sweden; M.D., Karolinska Institute, 1954). Wiesel was at Harvard, where he often collaborated with David Hubel, from 1959 until 1983. Together they showed that individual neurons in visual cortex responded optimally to specific stimuli: a line or edge at a particular orientation and, for the lowest-level neurons, particular locations. They also found that cells are organized in ocular dominance columns; series of columns alternative between responsiveness to the right and left eyes.Other research focused on binocular vision and the importance of early visual stimulation to normal development. They shared the Nobel Prize for Medicine and Physiology in 1981. In 1983 Wiesel moved to Rockefeller University.

Winograd, Terry (b. 1946, Maryland; Ph.D., Applied mathematics, MIT, 1970). Winograd has held positions in computer science and linguistics at Stanford University since 1974. In his early research he developed SHRDLU, a program that manipulates simulated blocks in a simulated space, and answers questions about them. Later Winograd repudiated this approach. Following in the tradition of Heidegger and Maturana, Winograd rejects the attempt to understand human intelligence in terms of the manipulation of representations. Among his most important publications are Understanding Natural Language (1972), Language as a Cognitive Process. Vol. 1: Syntax (1983), and Understanding Computers and Cognition: A New Foundation for Design (1987).

Winston, Patrick H. (1943, Peoria, IL; Ph.D., Computer Science, MIT, 1970). Winston's career has been spent with the AI Laboratory at MIT, where he is currently professor and Director. His research focuses on how vision, language, and motor faculties interact to account for intelligence. He is the author of Artificial Intelligence (1977, 1984, 1992), LISP (1984), and On to C++ (1994).

Wittgenstein, Ludwig (b. 1889, Vienna, Austria, d. 1951, Cambridge, UK). First interested in mechanical engineering, Wittgenstein turned to mathematics and the foundations of mathematics. In the Tractatus Logico-Philosophicus (1922) he developed an analysis of linguistic meaning built on logic and an analysis of picturing. Wittgenstein then left philosophy to become a school teacher in Austria; he later returned to teach at Cambridge from 1929 to 1947. In Philosophical Investigations (1953) Wittgenstein challenged his earlier account of language and traditional approaches to philosophy generally. He rejected the view that to possess a concept, or understand a word, is to possess explicit knowledge of necessary and sufficient conditions. According to Wittgenstein, what is involved is an implicit, inarticulable knowledge of the >family resemblances= between situations and objects.

Wundt, Wilhelm (b. 1832, near Mannheim, Germany, d. 1920; M.D., University of Heidelberg, 1855). Wundt spent the early part of his career at Heidelberg before being appointed professor of scientific philosophy at Leipzig in 1875, where he established the first institute for experimental psychology and created a journal devoted to experimental psychology, Philosophische Studien. Wundt was a major proponent of a scientific approach to psychology. In his Principles of Physiological Psychology (1874) he argued that conscious states could to be scientifically studied through the systematic manipulation of antecedent variables, and analyzed by carefully controlled techniques of introspection. Wundt also emphasized chronometric studies of mental processes; with respect to >higher= cognitive phenomena like linguistic behavior, Wundt favored a non-experimental, ethnographic methodology as expounded in his Volkerpsychologie ("ethnic psychology," or "group psychology"), a ten volume work published in 1920.

Zadeh, Lotfi A. (b.1921, Baku, Azerbaijan; Ph.D., Electrical Engineering, Columbia, 1949). Zadeh taught at Columbia University before moving in 1959 to the Department of Electrical Engineering and Computer Science at the University of California, Berkeley. Dissatisfied with classical logic as a tool for modeling human reasoning, Zadeh developed the formalization of fuzzy logic, starting with his 1965 paper Fuzzy sets. He is the author of Fuzzy Logic for the Management of Uncertainty(1992).

Zurif, Edgar (b. 1940, Montreal; Ph.D., Psychology, Waterloo, 1967). Zurif has spent his career at the School of Medicine of Boston University and in linguistics and psychology at Brandeis University. His work has focused on neurolinguistics; he is particularly known for reinterpreting the deficits in Broca=s versus Wernicke=s aphasia in terms of syntax versus semantics rather than production versus comprehension.