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What came before cognition? Enter Behaviorism • Philosophy of mind • Problem: Thorndike mixed his terms… • ..and the term “associationism” was picked up by John Watson and promoted in the form of learning theory… • …in spite of the well-established idea that sensory information is merely data on which preexisting mental structures act (e.g., Plato, early rationalism; Aristotle, early empiricism; Descartes, rationalism; Locke, empiricism; Kant, synthesis(?)…etc.) • Rationalism: – complexity is built into the organism • Empiricism: – idea that all knowledge comes from sensory experience 9/1/2005 1 Early Psychologists 2 Interesting aside 9/1/2005 5 e.g., Watson, Skinner – Promoted view that only externally measurable events (stimuli and responses) should be considered in understanding the mind – Behaviorists deny the utility of positing and relying on internal states to properly explain behavior • Thorndike observed… • …if no reward followed a response, the response would disappear – Thus, rewards were responsible for providing a mechanism for establishing a more adaptive response – Sounds like Darwin’s natural selection idea…and Thorndike was deeply influenced by Darwin 9/1/2005 4 e.g., Watson, Skinner – Promoted view that only externally measurable events (stimuli and responses) should be considered in understanding the mind – Behaviorists deny the utility of positing and relying on internal states to properly explain behavior • Fechner, Weber (psychophysicists) – Related physical properties of things like light and sound to the psychological experiences they produce in the observer • Ebbinghaus (late 1800s) – Decided complex processes like memory could be measured and analyzed • Thorndike (1911-published monograph on “Animal Intelligence: An Experimental Study of the Associative Processes in Animals”) – ‘Law of effect’ (e.g., response followed by reward would – be stamped onto organism as habitual response) – First general statement about the nature of associations 9/1/2005 9/1/2005 3 9/1/2005 6 1 Positive Feedback: Snowball effect Cybernetics • Examination of communication and control in living beings and their machines (1940s) – Postwar (WWII) focus on goal-directed machines • Louis Couffignal, 1958: – "the art of assuring efficiency of action” • Norbert Wiener, 1948: – from Greek kubernetes (pilot or rudder), first used by Plato in the sense of "the art of steering" or "the art of government " 9/1/2005 7 Importance of Feedback 9/1/2005 Copyright© 1997 Principia Cybernetica Copyright© 1997 Principia Cybernetica Copyright© 1997 Principia Cybernetica 10 Negative Feedback: Adaptive, goal-seeking behavior 8 Positive/Negative Feedback 9/1/2005 9/1/2005 9/1/2005 11 • Cybernetics Wiener, mathematician; founder of cybernetics movement; McCulloch, neurophysiologist, first to develop mathematical models of neural networks; von Neumann, mathematician; founding father in domains of game theory, quantum logic, axioms of quantum mechanics, the digital computer, cellular automata and selfreproducing systems 9 9/1/2005 12 2 Von Neumann was synthesizer and promoter of the stored program concept. His logical design of the IAS machine (from the Institute for Advanced Studies) became the prototype of most of its successors (e.g., von Neumann Architecture). End of Behaviorism? • Surprisingly, at a specific conference – MIT, September 11th, 1956 – Claimed by George Miller to be the birth date of cognitive psychology – In the same year, at a conference at Dartmouth, the term “Artificial Intelligence” was coined • Marvin Minsky, Claude Shannon (father of information theory) and many others in attendance 9/1/2005 Von Neumann with ENIAC 13 9/1/2005 16 Cognitive Revolution • Cognition: – Change from the dominance of behaviorism to cognitivism in approaches to understanding the mind – One version of the view that internal states are important to explaining behavior of complex systems 9/1/2005 14 9/1/2005 17 ‘Fathers’ of the Revolution • Noam Chomsky – Truly instrumental in challenging behaviorism’s dominance – Argued that a serious theory of mental processes should replace empiricism (that is, the belief that experience is the source of knowledge) as the dominant model in American science – Chomsky placed linguistics at the core of studies of the mind 9/1/2005 15 9/1/2005 18 3 • Established a new field of linguistics (generative grammar) based on a theory he worked on during the 1950s • In 1957, published “Syntactic Structures’, outlining his theory of transformationalgenerative grammar • Distinguished innate, unconscious knowledge (competence) of language from the way in which people actually use language (performance) • Argued that linguistic theory must account for universal similarities between all languages and for children’s ability to learn language 9/1/2005 19 Other Important Figures • James Tanner and John Swets – Applied signal detection theory and computer technology to study of perception • George Miller – Wrote “Magical Number Seven, Plus-or-Minus Two” • Jerome Bruner – Developmental psychologist who saw limited utility to associationist ideas in childhood learning; believed in higher-level processes involved in thinking, built upon representations and mental maps 9/1/2005 20 ‘Fathers’ of the Revolution • Newell & Simon – Wrote first AI program (General Problem Solver, or GPS) in 1959 – GPS was a theory of human problem solving stated in the form of a simulation program (that is, simulating a cognitive process) (Newell & Simon, 1972) – Theoretical framework of GPS had huge impact on direction of cognitive studies, introducing use of productions as a method for specifying cognitive models 9/1/2005 21 4