Learning Theory and Behaviour Modification

Stephen Walker

• Publisher: Routledge
• Year: 2017
• ISBN:
  9781351797597
• Edition: 1
• Topic: Psicología
• Subtopic: Behaviorismo

The ability to learn is of crucial importance in human life, but understanding this ability has proved to be difficult. There have been many attempts to formulate scientific theories based on both animal experiments and human experience; and these have been applied to education and the treatment of psychological disturbance, with a certain amount of success. Originally published in 1984, this incisive guide to the research and its outcomes provides the background to one of the most debated topics in psychology today.

Learning Theory and Behaviour Modification introduces the work of major figures, such as Pavlov and Skinner, which has strongly influenced theories in educational and clinical psychology, and formed the basis of the techniques known as 'behaviour modification'. As well as giving examples of these techniques the author relates new ideas about the scope and limits of behaviour modification to recent changes in the views of learning theorists. How much can experiments on animals tell us about human psychology?

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Introduction to learning theory

At some point, anyone reading this must have acquired a tendency to convert letters into sounds, and to associate strings of letters with the meanings of words. We cannot be certain exactly how this happened, but there is surely no doubt at all that it involved learning from experience. There may be some aspects of human language that remain uninfluenced by individual experience, but the spoken words I am using here are a result of my having learned English. There are many other languages which could be written with the same script, such as French or Spanish, but anyone who reads Russian, Greek or Hebrew will have had to learn a different set of visual signs as the alphabet, while the Arabic script is even more unfamiliar, and reading (or writing) in ancient Egyptian or Chinese is a different kettle of fish altogether.

Thus, the use of language requires a strong element of learning, and so does the knowledge of social custom and ritual, and all beliefs, loyalties and values that can be shown to differ from one culture to another, or from one generation to the next. And in many cases, it is quite obvious that even in the same culture or sub-culture one family may differ from another, or one person from another person, because of previous tragedies or traumas that may produce either weakness or strength of personality. More positively, they may differ because of family traditions or personal histories of practice and determination that may transmit or develop skills and expertise – whether musical, muscular or social.

Whether in academic education, specialized training, or in the more informal and unconscious adaptation to social and personal circumstances, there has always been a case to make that human life is largely dependent on individual learning – it is the flux, not the fixity, of human technologies and social institutions which most distinguishes our species from any other. Therefore, those who believe that they have found general laws, or universal principles, which apply to learning have often gone on to infer that the same general laws must underlie wider areas of human psychology, and can be used as general principles of human behaviour. The idea that the same theory can apply to all learning has often been attacked, both by those who think that innate factors determine human nature and by those who reject any ‘reductionist’ approach which tries to find underlying explanations for the complexities of life.

In spite of such criticisms, there are two quite separate reasons for continuing to study learning theories. The first is that this is still a vigorous research area, with technical advances in the design of experiments producing new answers to some of the old puzzles (Rescorla, 1980; Dickinson, 1980). The second is that the old theories themselves, despite numerous logical and metaphysical difficulties, have spawned a collection of practical measures, known as behaviour modification, or behaviour therapy, which have made a significant contribution to such areas as the treatment of severe neurotic phobias and the education of retarded or handicapped children.

The development of learning theory

Darwin

As I am writing in the centennial of the year of Darwin's death – 1882 – it is appropriate to acknowledge the Darwinian roots of some of the features of learning theories. In the conclusion to The Origin of Species, Darwin says: ‘In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation’ (Darwin, 1859/1968, p. 458). A new foundation for psychology exactly like this seems distant still, and an emphasis on the gradual evolution of mental powers and capacities is not really a characteristic of the theories I shall shortly review. But it is obvious that the Darwinian theory of evolution emphasizes the continuity of human and animal psychology, and the use of evidence from laboratory experiments on animal learning to test principles and specific hypotheses of supposedly wider application could almost be used as a definition of a learning theory.

In The Descent of Man (1871/1901) Darwin has two chapters on ‘Comparison of the mental powers of man and the lower animals’ whose aim is ‘to show that there is no fundamental difference between man and the higher mammals in their mental faculties’ (p. 99). Much of these is taken up with anecdotal evidence for the existence of wonder, curiosity, complacency and pride, as well as reason, abstraction and imagination, in mammals such as the baboon and the domestic dog. The conclusion is that ‘The lower animals differ from man solely in his almost infinitely larger power of associating together the most diversified sounds and ideas’ (Darwin, 1871/1901, p. 131), and ‘We must admit that there is a much wider interval between one of the lowest fishes, as a lamprey or lancelet, and one of the higher apes, than between an ape and man’ (p. 99). These assertions are used by Darwin to support his theory that human abilities could have evolved gradually from those of related species, rather than to forward the ‘new foundation’ for psychology which he had referred to earlier. However, by identifying the power of associations as a critical factor in human intelligence and firmly relating human mental capacities to those of animals, Darwin prepared the way for later ‘associationist’ theories about psychology which derive supporting evidence from animal experiments.

Pavlov and the conditioned reflex

When, in 1882, Darwin was buried in Westminster Abbey, a leader in The Times expressed full appreciation of his work. But, when The Descent of Man first appeared in 1871, The Times had thundered that ‘morality would lose all elements of stable authority’ if the public were to believe it. Few today suggest that the theory of natural selection (or in the case of The Descent of Man, sexual selection) is a threat to public order, although neither the religious Right nor the political Left have much enthusiasm for modern varieties of Darwinism such as sociobiology (Wilson, 1975).

Another branch in the roots of learning theory also ran into ideological resistance early on. In 1866 the St Petersburg Censorial Committee banned a popular book, and prosecuted its author for undermining public morals. The author was neither a pornographer nor a political theorist, but a physiologist called Sechenov, and the book was Reflexes of the Brain, which introduced the controversial suggestion that ‘all acts of conscious or unconscious life are reflexes’. Perhaps the authorities were especially sensitive, 1866 being the year of the first assassination attempt on Alexander II, but the case against Sechenov soon collapsed, and Reflexes of the Brain later made a deep impression on the young Ivan Pavlov (Gray, 1979).

Pavlov (1849–1936) was awarded a Nobel prize in 1904 for his work on digestion. In the lecture he gave in Stockholm when he received it, he described some of his findings as ‘conditioned reflexes’, although many of the more detailed experiments were to come later, as Pavlov became less concerned with digestion, and more concerned with ‘an investigation of the physiological activity of the cerebral cortex’ (the subtitle to Pavlov's Conditioned Reflexes, 1927). Sechenov's idea was that even the most complex manifestations of human psychology were made up of reflexes, that is of ways of reacting to stimulation of the sensory nerves by specific muscular or glandular activities. This gave Pavlov encouragement to build up from his rigorous experiments on digestive reflexes a theory which he applied to all cerebral functions.

Although Pavlov's work has been influential in a number of ways, the clearest contrast with Darwin is in his application of rigorous experimental method. Darwin had relied on anecdotal reports of casual and informal observations. For instance, he attributed abstract thought to dogs on the basis of a game he played with his pet terrier: Darwin would say ‘Hi, hi, where is it?’ in an eager tone, and the terrier would rush around, apparently hunting for something. ‘Now do not these actions clearly show that she had in her mind a general idea or concept that some animal is to be discovered or hunted?’ asked Darwin (1871/1901, p. 127). This is unsatisfactory because there are several other possibilities. The eagerness of Darwin's tone of voice may simply have excited the dog, since there were no experimental controls to show that saying ‘Where am I?’ or ‘How are you?’ to the terrier might not elicit an equal amount of rushing about.

Pavlov's observations were the opposite of casual. As a professional research scientist under three Tzars, and then both Lenin and Stalin, he was known for his emphasis on rigorous experimental method, and the physiological tradition in which he worked required reliable and repeatable experimental demonstrations. In much of the later work, scrupulous care was taken to avoid extraneous influences on psychological experiments by keeping the human experimenter separate from the experimental animal in a different room, and by going to such lengths as building the laboratories with double walls filled with sand to achieve sound insulation. What Pavlov discovered, in the course of his systematic study of digestion, is that glandular secretions, of gastric juices or of saliva, are controlled by ‘psychic’ or psychological factors, and not simply by chemical or mechanical stimulation. The earliest way in which this was demonstrated was by ‘sham feeding’.

It was primarily his skill as an experimental surgeon which enabled Pavlov to make his Nobel-prize-winning discoveries. Others, in the 1840s, had developed the technique of permanently implanting a metal tube in a dog's stomach, through which gastric juices could be collected. The modification introduced by Pavlov (and his co-worker, a Mrs Shumov-Simanovsky) was the surgical separation of the mouth from the stomach: the oesophagus was cut and the two cut ends were independently brought out at the throat. This meant that food eaten and swallowed by the dog dropped out of its throat before reaching the stomach, or alternatively, food could be dropped directly into the stomach without the dog's having seen or tasted it. The original purpose of this was to solve the problem of obtaining pure gastric juices, uncontaminated with food.

But, by the time of his Nobel lecture in 1904, Pavlov's main interest was in the psychological control of the gastric secretion. Bread dropped into a dog's stomach without the animal noticing it was not digested at all, but if the dog ate bread, gastric activity occurred even if the bread never reached the stomach. This all depended on the ‘appetite’ of the dog, since the mere sight of food produced stomach activity, but only if the dog took an interest in the food – the effectiveness of food in the mouth depends on how far the food ‘suits the dog's taste’ (Pavlov, 1955, p. 142).

In order to study these psychological factors in more detail it was not necessary to continue to work with secretions of the stomach, since secretions of the salivary glands can serve just as well. As every student knows, the standard Pavlovian experiment requires the measurement of salivation in response to an external and distant stimulus, such as the sounding of a buzzer. Dogs do not normally salivate when they hear buzzers, even if they are hungry, but, if the buzzer is always sounded a few seconds before food is to be presented, a ‘conditioned reflex’, of salivating to the sound, is formed. To establish a reliable response, a dog might be given half-a-dozen pieces of meat, each preceded by the sounding of the buzzer, at five-minute intervals every day for a week or more. After this, a demonstration of the ‘conditioned reflex’ could be given by simply sounding the buzzer, without giving any meat. Now the buzzer would produce the same effects, more or less, as showing the dog real food – there would be plenty of salivation, and the dog would lick its lips, look at the food dispenser and perhaps wag its tail.

More details of Pavlov's experimental findings will be found in chapter 3. The laboratory findings with the reflex of salivation were used as the basis for a theory about the ‘higher nervous activity’ of the mammalian cerebral hemispheres, and then for wide-ranging speculations about psychology and psychiatry. The dog salivates to the buzzer only because of its previous experience of the association in time of the buzzer with its food. The conditioned reflex could thus be seen as an atomic unit of learning from experience, capable of being ‘synthesized’ into more complex combinations by the activities of the cerebral cortex. Thus Pavlov was led to claim that ‘the different kinds of habits based on training, education and discipline of any sort are nothing but a long chain of conditioned reflexes’ (Pavlov, 1927, p. 295, my italics).

In some ways this set the pattern for subsequent learning theorists. In the last two pages of his Conditioned Reflexes, the most systematic exposition of his work, Pavlov reiterates his objective of providing a ‘purely physiological interpretation’ of brain activity immediately after asserting that his experiments would eventually ‘throw some light upon one of the darkest points of our subjective self – namely, the relations between the conscious and the unconscious’ (Pavlov, 1927, p. 410). Obviously, this harks back to Sechenov's slogan that ‘all acts of conscious or unconscious life are reflexes’, but, sadly, relations between conscious and unconscious processes are usually neglected in developments based on Pavlov's work.

Thorndike (1874–1949): connectionism and the law of effect

Pavlov often described stimuli such as the buzzer, which came to elicit salivation, as ‘signals’ for food, which might direct the animal to acquire food, and assist in its adaptation to the external world. But partly because in his experiments the dogs were firmly strapped in stands, he saw the formation of conditioned reflexes as a rather passive and mechanical process. Thorndike is important in learning theory for proposing an equally mechanical process of learning, but also for emphasizing the effects of consequences of the active response of an experimental animal. We may note, however, that Pavlov was not unaware of the influences of the consequences of an animal's actions, and made a special point in 1895 of mentioning an anecdote to illustrate this. Pavlov's most famous operation was the construction of ‘Pavlov's pouch’ (Gray, 1979) – a piece of the duodenum containing the outlet of the pancreas is cut away and then stitched back facing outwards so that it discharges through an opening in the abdomen, and its secretions can be subsequently collected. A difficulty with this was that the escaping digestive juices, leaking out during the night, caused erosion and bleeding of skin of the abdomen. One of the dogs subjected to his operation and left tied up in the laboratory overnight was found, two nights in succession, to have torn a heap of plaster from the wall. On the second occasion Pavlov noticed that the dog had been sleeping on the plaster, with the result that the skin of its abdomen was in exceptionally good condition. From then on all the animals that had had a similar operation were provided with a pile of sand or old mortar to lie on, which greatly reduced the incidence of skin irritations. Pavlov remarks: ‘We gratefully acknowledge that by its manifestation of common sense the dog had helped us as well as itself. It would be a pity if this fact were lost for the psychology of the animal world’ (Pavlov, 1955, p. 90).

Thorndike (1898) ensured that the tendency of animals to learn to help themselves was not lost to learning theory, but was reluctant to acknowledge anything approaching common sense on the part of the dogs, cats and chicks which were the subjects of his behavioural experiments. Whereas Pavlov brought to animal psychology a fully equipped physiological laboratory, Thorndike was influenced by the philosophical views of William James and by the fact that as a postgraduate student at Harvard in the 1890s he could conduct animal experiments only by keeping chickens, young cats and dogs in his own lodgings, and building his own apparatus. Not surprisingly, Thorndike was unpopular with landladies, and at one point, when Thorndike had been turned out for hatching chickens in his bedroom, William James's household had to take in both Thorndike and chickens. James's Principles of Psychology (1891) pours considerable scorn over Darwin's and Romanes’ anecdotal evidence of reasoning in animals, and proposes that all their associations of ideas take place by simple contiguity. When an animal reacts intelligently to some stimulus, it is because ‘the beast feels like acting so when these stimuli are present, though conscious of no definite reason why’ (James, 1891, p. 350). In particular, when any animal opens a door or gate by biting or manipulating a latch or handle, James suggests that this is likely to be ‘a random trick, learned by habit’ (James, 1891, p. 353). Thorndike's bedroom experiments were designed to support these views of William James, which in many ways represented a reaction against Darwinian anthropomorphism and a return to the sceptical view of animal reason put forward in the seventeenth century by the English philosopher John Locke.

The main technique which Thorndike used to provide experimental evidence in support of James's view involved the use of problem or puzzle boxes, with cats (the barking of dogs having caused excessive trouble with landladies). The boxes were small crates, hammered together from wooden slats, about 50 cm square and 30 cm high. Anyone who has ever put a cat in a carrying box will know that they do not always take kindly to it, and Thorndike's animals, alt...