Psychology

Neurons Image credit: Brain Maps Chick cerebellum drawn by Ramon y Cajal

Behaviourism arouse in the early 20th century as a response to Austrian physician Sigmund Freud's psychoanalysis. In 1913, American psychologist John Watson argued that psychology should be a science of behaviour, not of the mind (Watson, pp.158-177). Behaviourism rejects the idea that internal mental states like qualia exist. Watson was influenced by the idea of classical conditioning, discovered by Russian physiologist Ivan Pavlov in 1897 (Pavlov, 1902). In 1920 Watson and his assistant Rosalie Rayner used classical conditioning to make an eleven month old baby, Albert, fear stimulus which would not normally be feared, such as a white rat. Albert soon generalised the response so that he was afraid of anything furry (Watson and Rayner, pp. 1-14).

Further criticisms of psychoanalysis arose in 1948, when American psychologist Burrhus Frederic Skinner argued that thoughts and feelings are merely examples of behaviour (Skinner, pp.168-172). Three years later, German-British psychologist Hans Eysenck, argued that some personality traits are genetic (Eysenck and Prell, pp.441-465) and in 1963, Austrian-British philosopher Karl Popper argued that psychoanalysis is not a science because it cannot be falsified (Popper, 2002). Popper argued that science can be distinguished by the fact that it makes unique predictions which can be proven false.

Behaviourism became less popular in the mid 20th century. In 1959, American linguist Noam Chomsky showed that behaviourism cannot explain how people can produce an infinite variety of sentences unique in structure and meaning (Chomsky, pp.26-58). He suggested that there must be internal mental structures. The term cognitive science was coined by English chemist Christopher Longuet-Higgins in 1973 (Longuet-Higgins, pp.35-37).

Cognitive science accepts the neuron doctrine, it shows that signals in the brain are mostly sent through networks composed of millions of neurons. Neurons receive stimulus from branches known as dendrites and then communicate this information across a synapse, either electrically or chemically. At electrical synapses a nerve impulse is fired along an axon, this crosses a gap junction to connect to the dendrite of another neuron. At chemical synapses electrical impulses are converted into chemical signals, this process is called exocytosis and it is slower than electrical transmission.

Identity theory was first suggested by English philosopher Ullin Place in 1956 (Place, pp.44-50) and was extended by British-Australian philosopher Jack Smart three years later (Smart, pp.141-156). Identity theory suggests that particular states of the mind are identical to particular states of the brain. This approach was criticised by American philosopher Hilary Putnam in 1960 (Putnam, pp.148-180). Putnam argued that the same sensations can arise from different brain states, an animal may see the same thing as a human but this image will correspond to different parts of the brain. Putnam argued that the mind is more like a computer.

In 1965, American philosopher Jerry Fodor argued that the mind can be explained in functional terms, this means anything that performs the function of a mind, is a mind and is therefore conscious (Fodor, pp.161-179). Functionalism has been criticised by the Chinese room argument, presented by American philosopher John Searle in 1980 (Searle, pp.417-457).

Material theories of the mind must be able to solve the problems raised by Descartes. They must be able to explain the existence of qualia, state where qualia exist within the brain and explain why it does not appear possible to divide or duplicate our consciousness. Any material theory of the mind must also explain the inherent subjectivity associated with our conscious experiences.

References

Broca, P.P., 1861, 'Loss of Speech, Chronic Softening and Partial Destruction of the Anterior Left Lobe of the Brain', Bulletin de la Societe Anthropologique, Green, C.D. (trans.), Vol.2, pp.235-238 and Broca, P.P., 1861, 'Remarks on the Seat of the Faculty of Articulated Language, Following an Observation of Aphemia (Loss of Speech)', Bulletin de la Societe Anatomique, Green, C.D. (trans.), Vol.6, pp.330-357

Chomsky, N., 1959, 'A Review of B. F. Skinner's Verbal Behavior', Language, Vol.35

Eysenck, H.J. and Prell, D.B., 1951, 'The inheritance of neuroticism: An experimental study', Journal of Mental Science, Vol.97

Finger, S., 2001, 'Origins of neuroscience: a history of explorations into brain function', Oxford University Press, Oxford

Fodor, J., 1965, 'Explanations in psychology', Philosophy in America, Black M. (ed.), Allen and Unwin, London

Golgi, C., 1906, 'The neuron doctrine-theory and facts', Nobel Lectures: Physiology or Medicine. See also Ramón y Cajal, S., 1991, 'Cajal's degeneration and regeneration of the nervous system', DeFelipe, J., Jones, E.G., (trans.), Oxford University Press, Oxford

Kim, A., 2006, 'Wilhelm Maximilian Wundt', Stanford Encyclopedia of Philosophy

Longuet-Higgins, H. C., 1973, 'Comments on the Lighthill Report and the Sutherland Reply', Artificial Intelligence: a paper symposium, Science Research Council

Pavlov, I.P., 1902, 'The work of the digestive glands', Charles Griffin

Place, U.T., 1956, 'Is Consciousness a Brain Process?', British Journal of Psychology, Vol.47

Popper, K.R., 2002, 'Conjectures and refutations: the growth of scientific knowledge', Routledge, London

Putnam, H., 1960, 'Minds and Machines', Dimensions of Mind, Hook, S. (ed.), New York University Press, New York pp.148-180 reprinted in Putnam, H., 1979, 'Mind, Language and Reality', Cambridge University Press, Cambridge, pp. 362-385

Searle, J., 1980, 'Minds, Brains and Programs', Behavioural and Brain Sciences, Vol.3

Skinner, B. F., 1948, '"Superstition" in the pigeon', Journal of Experimental Psychology, Vol.38

Smart, J.J.C., 1959, 'Sensations and Brain Processes', Philosophical Review, Vol.68

Watson, J.B., 1913, 'Psychology as the Behaviorist Views it', Psychological Review, Vol.20

Watson, J.B. and Rayner, R., 1920, 'Conditioned emotional reactions', Journal of Experimental Psychology, Vol.3