Introduction: What is Cognitive Science? Typeset by FoilTEX 1

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1 Introduction: What is Cognitive Science? Typeset by FoilTEX 1

2 Cognitive science is the interdisciplinary study of mind and intelligence philosophy psychology neuroscience artificial intelligence linguistics anthropology Cognitive science is the interdisciplinary scientific study of the mind and its processes. It examines what cognition is, what it does and how it works. It includes research on intelligence and behavior, especially focusing on how information is represented, processed, and transformed (in faculties such as perception, language, memory, reasoning, and emotion) within nervous systems (humans or other animals) and machines (e.g. computers). Cognitive science consists of multiple research disciplines, including psychology, artificial intelligence, philosophy, neuroscience, linguistics, and anthropology. It spans many levels of analysis, from low-level learning and decision mechanisms to high-level logic and planning; from neural circuitry to modular brain organization. The fundamental concept of cognitive science is that thinking can best be understood in terms of representational structures in the mind and computational procedures that operate on those structures. Typeset by FoilTEX 2

3 History of cognitive science: preliminary remarks Philosophy: Fundamental questions since Aristotle and Plato: 1. What is the nature of mind? Metaphysics and nature of reality 2. What is the nature of knowledge? Epistemology and nature of knowledge Psychology:, 1890s. Behaviorism: can t study what is in the mind (from philosophical psychology towards experimental psychology ) 1950 s. Miller, etc.: mind has structure 3. How do we think? Neuroscience: 4. How does the brain make a mind? Artificial intelligence: Minsky, Newell, Simon, Mc- Carthy 5. How to construct mind? Linguistics :1956. Chomsky versus behaviorist view of language. 6. Language acquisition and evolution. Innateness? Anthropology: social, cultural aspects of knowledge 7. Is there any cultural difference in the thinking of people? Typeset by FoilTEX 3

4 Cognitive science is the interdisciplinary study of mind and intelligence The need of INTEGRA- TION: How can all these fields, with different histories and methodologies can be integrated to produce an understanding of mind? Typeset by FoilTEX 4

5 Key concepts Mental representation Computational procedures Thinking = Mental representaions + computational procedures more precisely: Thinking = representational structures + procedures that operate on those structures. Analogy between computation and thinking: data structures mental representations + algorithms + procedures = running programs = thinking Methodological consequence: study the mind by developing computer simulations of thinking Typeset by FoilTEX 5

6 Philosophy from the Greek philosophers to the age of reason Aristotle: logical inference; knowledge from experience rule-based knowledge Plato: What is knowledge? concepts are innate rationalism: Plato, Descartes, Leibniz: knowledge can be gained by thinking and reasoning empirism: Aristotle, Locke, Hume: learning be experience Kant: combination of rationalism and empirism Further reading: Typeset by FoilTEX 6

7 Philosophy monism vs. dualism The brain - mind problem reductionism emergentism functionalism downward causation Typeset by FoilTEX 7

8 Philosophy Monism: is the theory that there is only one fundamental kind, category of thing or principle. Dualism: is the theory that the mental and the physical or mind and body or mind and brain are, in some sense, radically different kinds of thing. (Interactionist dualism from Descartes to Popper and Eccles) Monism versus dualims Typeset by FoilTEX 8

9 Philosophy Reductionism Philosophical position: a complex system is nothing else but the sum of its parts Methodological reductionism: a problem (the object of explaining something) is split up into separate parts or aspects and thus reduced to simpler components Epistemological reductionism: higher level phenomena can be explained by processes at a lower level Ontological reductionism: reality is composed of a minimum number of kinds of entities or substances. Typeset by FoilTEX 9

10 Philosophy Emergentism is a theory concerning the nature of the material world. In contrast to reductionistic materialism, which asserts that only the tiniest components of matter have unique properties, emergentism maintains that along with complexity, and especially with structure and function, go properties that are unique and that are not to be found in the tiniest components of matter. These properties of more complex systems are therefore not reducible to those of their constituent elements, though they could not exist without them. While many of the fundamental properties of matter, such as mass, are held to be merely quantitative and additive, emergent properties are said to be qualitative and novel or nonpredictable. Jaegwon Kim proposes (using the chart on the right) that M1 causes M2 (these are mental events) and P1 causes P2 (these are physical events). P1 realises M1 and P2 realises M2. However M1 does not causally effect P1 (i.e., M1 is a consequent event of P1). If P1 causes P2, and M1 is a result of P1, then M2 is a result of P2. He says that the only alternatives to this problem is to accept dualism (where the mental events are independent of the physical events) or eliminativism (where the mental events do not exist). Typeset by FoilTEX 10

11 Philosophy Functionalism Functionalism is the doctrine that what makes something a thought, desire, pain (or any other type of mental state) depends not on its internal constitution, but solely on its function, or the role it plays, in the cognitive system of which it is a part. More precisely, functionalist theories take the identity of a mental state to be determined by its causal relations to sensory stimulations, other mental states, and behavior. An illustration of multiple realizability. M stands for mental and P stands for physical. It can be seen that more than one P can instantiate one M, but not vice versa. Causal relations between states are represented by the arrows (M1 goes to M2, etc.) Typeset by FoilTEX 11

12 Philosophy Downward Causation all processes at the lower level of a hierarchy are restrained by and act in conformity to the laws of the higher level (Donald T. Campbell) specifically: mental agents can influence the neural functioning (Sperry, Szentágothai) There is a feedback from the effect to the cause CYBERNETICS: a great tradition (i.e. a causal chain from emergent mental phenomena downward upon the physiological functions of neural structures) it was suggested that the nervous system can be considered as being open to various kinds of information here would be no valid scientific reason to deny the existence of downward causation, or more precisely, a two-way causal relationship between brain and mind Typeset by FoilTEX 12

13 Psychology George Miller: The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information (1956) From behaviorism to cognitive science Short-term memory could only hold seven plus or minus two chunks of information a chunk is any meaningful unit:digits, words, chess positions, or people s faces The concept of chunking and the limited capacity of short term memory became a basic element of all subsequent theories of memory. Finite capacity of human thinking Information Processing Memory models The cognitive revolution is the name for an intellectual movement in the 1950s that began what are known collectively as the cognitive sciences. It began in the modern context of greater interdisciplinary communication and research. Typeset by FoilTEX 13

14 Experimental methods and disciplines Levels Neural representation: cells, networks, modules Neural computation versus computational neuroscience Cognitive Neuroscience Neuroscience Typeset by FoilTEX 14

15 Artificial intelligence Dartmouth Conference the first running AI program, the Logic Theorist (LT): Allen Newell, J.C. Shaw and Herbert Simon (1957) The General Problem Solver (GPS) demonstrated by Newell, Shaw and Simon first game-playing program, for checkers, to achieve sufficient skill to challenge a world champion:arthur Samuel 1958 LISP language: John McCarthy: 1958 Teddington Conference on the Mechanization of Thought Processes: UK John McCarthy s Programs with Common Sense, Oliver Selfridge s Pandemonium, and Marvin Minsky s Some Methods of Heuristic Programming and Artificial Intelligence. ; 1958 Typeset by FoilTEX 15

16 Linguistics Noam Chomsky versus behaviorist view of language. Innateness : universal grammer rejected behaviorist assumptions about language as a learned habit proposed instead to explain language comprehension in terms of mental grammars consisting of rules generative grammar: Syntactic Structures Chomsky argues that the experiences available to language learners are far too sparse to account for their knowledge of their language. To explain language acquisition, we must assume that learners have an innate knowledge of a universal grammar capturing the common deep structure of natural languages. It is important to note that Chomsky s language learners do not know particular propositions describing a universal grammar. They have a set of innate capacities or dispositions which enable and determine their language development. Chomsky gives us a theory of innate learning capacities or structures rather than a theory of innate knowledge.. Typeset by FoilTEX 16

17 Antrophology Ethnography, but pay attention to how people think Like psychology, but less experimental, more cross cultural Psychologists are also doing crosscultural studies Typeset by FoilTEX 17