Return of Cognition The Decline of Behaviourism –What couldn’t it explain? Cognitive Processing –Bartlett (Cambridge) –Broadbent (Cambridge) –Bruner (Harvard) –Chomsky (MIT) –Craik (Cambridge) –McCulloch (Chicago, MIT), Pitts (Chicago, MIT) –Miller (Harvard) –Newell (CMU) –Piaget (Geneva) –Shannon (MIT) –Simon (CMU) –Turing (Cambridge) –Weiner (MIT) See

The Decline of Behaviourism The organisation of behaviour –According to behaviourism complicated behaviours emerge from a complex chain of associations learned over repeated learning trials –However, by the 1950s it was clear that this explanation did not work It would simply take more time than was available… The rise of instincts –The work of Lorenz and Tinbergen, the founders of ethology, suggested that the commitment to the stimulus environment found in behaviourism was inadequate, e.g. imprinting. The uniqueness of language –In the 1950s psychologists came to the conclusion that language is uniquely human and that the application of animal models of learning was simply inappropriate.

Jean Piaget ( ) His work predates the cognitive (r)evolution that occurred in both the US and Europe. His research in developmental psychology and genetic epistemology had one unique goal: how does knowledge grow? –the growth of knowledge is a progressive construction of logically embedded structures superseding one another by a process of inclusion of lower less powerful logical means into higher and more powerful ones up to adulthood. By assuming that complex representations could be created, modified, extended and essentially discarded he radically changed way we think about child development and human cognition

Sir Frederic Bartlett ( ) Bartlett (1932) – What happens when someone reads or listens to a story and tries to recall it? –The ‘War of the Ghosts’ the recalled passages always become shorter and more coherent. the person remembering selects features of the passage to anchor the whole story. detail is sometimes changed so as to become more familiar to the rememberer Schema –Bartlett suggested that memory is organized by schema which provide a mental framework for understanding and remembering information. –These schema(ta) are used in the active reconstruction of events.

Kenneth Craik ( ) Kenneth Craik studied philosophy at the University of Edinborough before moving to Cambridge He is best known for his book ‘The Nature of Explanation’ (1943) wherein he suggested that the mind constructs models of reality “If the organism carries a small-scale model of external reality and its own possible actions within its head, it is able to try out various alternatives, conclude which is the best of them, react to future situations before they arise, utilize the knowledge of past events in dealing with the present and future, and in every way react to a much fuller, safer and more competent manner to emergencies which face it” (Craik, 1943, p.57) This book was essentially a philosophical treatise concerning a number of traditional philosophical questions but it made a radical departure with it’s hypotheses about the nature and function of thought.

Alan Turing ( ) During his short, and generally unhappy life, he contributed to mathematics, cryptanalysis, logic, philosophy, and biology and indirectly influenced psychology and the development of artificial intelligence In 1935, at the age of 22, he invented abstract computing machines, now known simply as Turing Machines, on which all digital computing is now based He wrote an unpublished manuscript which was later to be known as the Manifesto for Artificial Intelligence developing such ideas a networks of learning neurons (see connectionism He is most famous in Psychology and Philosophy for the Turing Test (1950).

The Turing Test The Turing test involves a computer, and two humans: the interrogator and the foil –The interrogator attempts to determine, by asking questions of the others, i.e., the computer and the human foil, which is the computer. –The foil must help the interrogator to make a correct identification. –A number of different people play the roles of interrogator and foil. –If enough interrogators cannot correctly decide which is the computer then the conclusion to be drawn is that the computer can think

McCulloch & Pitts (1943) McCulloch and Pitts published “A Logical Calculus of the Ideas Immanent in Nervous Activity" in (1943) Their computational neurons had the following properties –They are binary devices –Each neuron has a fixed threshold –The neuron receives inputs from excitatory synapses, all having identical weights. –Inhibitory inputs have an absolute veto power over any excitatory inputs. –At each time step the neurons are simultaneously updated by summing the weighted excitatory inputs and setting the output to 1 iff the sum is greater than or equal to the threhold AND if the neuron receives no inhibitory input. Using these constraints they could model any Boolean logic problems, e.g. AND, NOT, OR etc.

Norbert Weiner ( ) An American mathematician who invented cybernetics (the study of communication and control typically involving feedback) –Published "Behaviour, purpose, and teleology" (Rosenblueth, Wiener, & Bigelow, 1943). The main theme of the paper is a classification of types of behaviour with special reference to the concept of purpose. –In 1948 he published Cybernetics; or, Control and Communication in the Animal and the Machine Behaviour was divided into two types –Active: the energy for the behaviour is internal Goal-oriented –Requiring Feedback or Not. Non-goal oriented –Passive: the energy for the behaviour is external

Claude Shannon ( ) In 1948 he published A Mathematical Theory of Communication without which the cognitive (r)evolution would probably have not have happened. –Information can be measured in terms of uncertainty –Using binary logic, i.e. yes/no questions, it is possible to quantity information E.g. Which face of a die is showing? (Assume the answer is 2) –Is it greater than three? –Is it less than three? –Is it less than two? Three questions are equivalent to 3 bits (binary digits) of information Introduced and/or discussed such concepts as information theory, channels, noise, filters, capacity, degradation each of which has continued to influence modern psychological thinking.

Jerome Bruner ( …) Bruner (and colleagues, Goodnow & Austin) published ‘A Study of Thinking’ in 1956 On the cognitive revolution –“It was, we thought, an all-out effort to establish meaning as the central concept of psychology - not stimuli and responses, not overtly observable behavior, not biological drives and their transformation, but meaning. It was not a revolution against behaviorism with the aim of transforming behaviorism into a better way of pursuing psychology by adding a little mentalism to it….. It was an altogether more profound revolution than that. Its aim was to discover and to describe formally the meanings that human beings created out of their encounters with the world, and then to propose hypotheses about what meaning-making processes were implicated. It focused on the symbolic activities that human beings employed in constructing and making sense not only of the world, but of themselves” (Bruner, Acts of Meaning, 1990, p2)

George Miller ( ) Founded the Center for Cognitive Studies, Harvard, in 1960 with Bruner “The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information”, (Psychological Review, 1956) –A limited short term memory processor –Chunking Plans and the Structure of Behaviour, (Miller, Galanter & Pribram, 1960) –Planning –TOTE (test-operate-test-exit)

Donald Broadbent ( ) Broadbent was one of the many instigators of the cognitive revolution –In 1958 he published Perception and Communication –In this book Broadbent pulled together diverse work on information theory and early computational modelling showed how attentional processes can be studied rigorously through experimentation Explained attention using information-processing constructs Used behavioural data to infer the functional stages of attentional processing

Avram Noam Chomsky ( ) In 1957 B.F. Skinner published Verbal Behaviour a behaviourist account of the acquisition and use of language In 1959 Chomsky published a review of the book ( –Skinner’s behaviourist terms (e.g. stimulus, response, etc) are fine for animal learning but need to be modified to apply to human behaviour In particular they do not apply to language and when extended metaphorically to language there meaning is so vague as to be practically meaningless –Given the flexibility of language use in any particular context the stimulus/response/reinforcment paradigm has little predictive value He argued that no behaviourist account of language would ever be able to account of language’s inherent flexibility and creativity. –These aspect’s of language can only be understood by assuming that language is a rule governed system. However…

Allen Newell ( ) Working with Shaw and Simon in the 1950s, 1960s, and 1970s and developed a number of important computational approaches to psychology –Information Processing Languages –Logic Theory Machine –General Problem Solver –Production system languages (e.g. OPS5) Later, in the 1980s, with PhD students Laird and Rosenbloom, he developed a complex production system cognitive architecture –SOAR Continued to challenge the goals and purposes of Psychology with his book Unified Theories of Cognition (1992) which was based on his William James (1987) lectures which is fundamentally an extension of his 1973 paper You can't play 20 questions with nature and win

Herbert Simon ( ) One of only two researchers in Psychology (the other is Daniel Kahneman) to be awarded a Nobel prize (in Economics!!!) Held chairs at CMU in… –Psychology, Philosophy, Economics and Computer Science With Allen Newell and others he pioneered Artificial Intelligence as it applies to Psychology publishing the classic The Sciences of the Artificial in 1969 Also with Allen Newell he demonstrated that problem solving could be studied in a meaningful way culminating in the classic text Human Problem Solving (1972) Developed the idea that expertise was due to the development of ‘chunks’ (see G. Miller) with as many as 50,000 learned by the time someone is an expert. Developed Verbal Protocol Analysis as a method of data collection and analysis (with K.A. Ericsson) in the book Protocol Analysis: Verbal Reports as Data.