Presentation on theme: "Approaches to Psychology PS1012 & PS1014. John Beech"— Presentation transcript:
1 Approaches to Psychology PS1012 & PS1014. John Beech The Cognitive Approach to Psychology
2 Cognitive Approach Two sections: Paradigms of the cognitive approach. The historical development of the cognitive approach.
3 What is Cognitive Psychology? “It is concerned with thinking and the mental processes related to it.” (Glassman, 2000).Examples: perception, thinking, memory and language.Cognition: you can’t fully explain behaviour by stimulus-response connections.
4 Some cognitive paradigms and/or concepts: A preview Filters (e.g. Broadbent)Categorisation (e.g. a “poodle” is within the set of dogs)Mental set – priming our expectationsThe executive – how we control our own actions.Different memory storesModularity – the mind as a number of independently operating devices.
5 Some cognitive Paradigms: 1. filters This was one of the early concepts. Filters help the problem of information overload by reducing information. Broadbent (1958) was especially attracted to the notion. In his model the filter took out unwanted information prior to the single perceptual system. This restricted incoming flow.The filter can act visually, verbally or in other ways. Visually it can operate to restrict the field of vision. An emotional filter might operate so that one can block out violence parts of a film. In word recognition experiments presenting taboo words, taboo words are slower at being recognised. This could be due to a filter. On the other hand it may just be a word frequency effect.
6 FiltersWork in the 1950s demonstrated that it is possible to affect emotionally the unconscious processing of information.Lazarus and McCleary (1951) gave certain nonsense syllables (e.g. vag, mig, jek) paired with a slight electric shock at the same time. Other syllables in the list did NOT have a shock.Later they presented all the syllables (this time without any shocks) and those previously paired with shocks evoked galvanic skin responses, whereas the others didn’t. (In other words their sweat glands registered that they were emotionally reacting to these particular syllables, but not to the others.)
7 FiltersFurther work by researchers in the 1990s have repeated these findings using more sophisticated techniques. Thus people can acquire emotional conditioned responses.This later work also showed that stimuli can be presented subliminally and be paired with a mild shock, and this too can result in an emotionally conditioned response. Thus one doesn’t even need to be aware of the stimulus being presented to acquire an emotional response to it!
8 Paradigms: 2. categorisation Categories refer to how we group entities together. For instance, we understand there are oaks and beeches that are trees. Trees are plants, etc.From the time of Aristotle the classical view has been that categories are subjectively formulated and subject to our society and language. These categories have critical attributes that specify membership. Finally, the boundaries between the categories are not fuzzy.
9 Paradigms: 2. categorisation The philosopher Ludwig Wittgenstein ( ) had challenged this classical view and various experimental studies began to question it as well.Brown and Lenneberg (1954) examined our classification of colour. A first group of participants (from the USA) were given 24 colours to name. These varied in the ease with which they could be named. So they were able to rate the colours in terms of how easy they were to name.
10 Paradigms: 2. categorisation The next group were shown a small set of colours and then given a recognition test that included the original set. They had to say which they’d seen before in the first set. Found: colours that were easier to name were recognised better. Concluded that being able to name colours helped recognition.
11 Paradigms: 2. categorisation However, Eleanor Rosch Heider (1970) studied the Dani in New Guinea, who were Stone Age people. They had only 2 colour words: mola for bright warm colours and mili for dark cold ones.They had to name 40 different colours and then given a recognition test. When naming they were in agreement about the mola and mili colours, but not for the other colours.However, in the recognition part, unexpectedly, they performed like the American participants making the same confusions. Thus naming does not appear to affect our conceptualisation of colour.
12 Paradigms: 2. categorisation The classicist view had been that as the lines of demarcation between colours was arbitrary, different cultures had imposed different boundaries and these would be internalised by individuals within their particular cultures.The results of the Rosch Heider expt suggested that the physiology of the coding of colour is more important. In this new view “prototypes” are a central member of a category, eg. A robin is a better prototype of “bird” than “stork”. She also believed that there could be fuzzy boundaries between categories. Her position came to be known as the “natural” view of concepts.
13 Paradigms: 3. priming or mental set “Mental set” was an area of interest for a long period. S given an expectation about what is going to be seen. For instance, in one experiment in the 1930s words presented briefly on tachistoscope. The words were misspelled. One group thought they were getting a list of names of animals, and the other a list about travel. The word sael was read as “seal” by the animal group and as “sail” by the travel group.
14 Paradigms: 3. priming or mental set Another example was Rubin’s vase which is seen as two faces or a vase, depending on how it is introduced beforehand.
15 Paradigms: 3. priming or mental set Cognitive psychology used the term “priming”. E.g. when naming a list of words, if fruit is followed by orange, this speeds response to orange. Giving the semantic category has helped the exemplar.Kay and Marcel (1981) presented a mix of words and non-words. If couch was followed by louch, louch was pronounced as “lowch”. But if it was preceded by touch, it was pronounced as “luch”. The pronunciation of the non-word was being primed by the previous word.
16 Paradigms: 4. the executive: The Baddeley & Hitch (1974) model This is about the hypothesised decision-maker in the head. The executive has had many roles. E.g. in the Selfridge model there was the decision demon. In Baddeley and Hitch’s model of working memory there are two slave systems, one an articulatory (phonological) loop, the other a visual-spatial scratch pad. But he also has an executive to co-ordinate the systems.
17 Paradigms: 4. the executive It has been criticised (e.g. by Tulving, 1972) as modellers who use this device appear to give it human qualities.
18 Paradigms: 4. the executive: The Baddeley & Hitch (1974) model Posner (1978): the problem of the “homunculus”, the miniature person who takes executive decisions. But the behaviour of the homunculus must also be explained. This provides the problem of infinite regression.
19 Paradigms: 5. Memory stores: Atkinson & Shiffrin (1968) This was a very powerful model at the time that took over from the influential Broadbent model. It had 3 stores: a “sensory memory” (SM) “short-term memory” (STM), a “long-term memory” (LTM). It also has a “rehearsal buffer” linked to STM. Information in the working store STS decays within seconds. But processing can be put in the rehearsal buffer. The longer it is held in the rehearsal buffer, the greater the likelihood of transfer to LTM. STM has 7 slots, each for a chunk of information. LTM is much more permanent and is essentially limitless.
21 Paradigms: 5. Memory stores - Atkinson & Shiffrin (1968) LTM appears to have a number of different locations in the brain. Eg. A stroke victim lost the ability to name vegetables, but could still describe each vegetable, suggesting different locations for names and for knowledge about vegetables.Although essentially simple, Atkinson and Shiffrin’s model became immediately adopted and very successful. It was probably the most successful information-processing model of the era. However, citations to it gradually declined.
22 Paradigms: 6. modularity Fodor (1983) argued that the mind is better considered as a number of separate, mainly independent, devices. These are specialised for particular kinds of analysis in a fast manner. Only after this rapid processing will communication between devices take place.One implication for modularists such as Fodor is that there is no need for an executive function.Gardner (1985), who is sympathetic to modularity sees that there is a danger of Psychology fractionating into the study of these different functions without any unifying overviews.
23 Paradigms/concepts – a summary 1. Filters – we examined this concept by Broadbent, but it can be applied in different contexts – even emotionally.2. Categorisation – the classical view is that items are categorised into distinct sets and that our classification system is driven by language. But anthropological work suggests that at least for the perception of colours our classification of these is not determined by language. We might use prototypes to conceptualise categories and there could be fuzzy boundaries between concepts.3. Mental set – or “priming” in modern parlance. If we are presented with a stimulus beforehand it can affect the way we process a second stimulus. This can even affect how we pronounce a non-word (Kay & Marcel, 1981).4. The executive – we looked at the homunculus problem.5. Different memory stores – the Atkinson & Shiffrin (1968) model has been particularly successful.6. Modularity – no need for an executive according to Fodor as the mind is a number of independently operating devices.
24 Overview Early beginnings: Bartlett. Background influences: computing, cybernetics, information theory and war.Early part of cognitive revolution: Miller, Broadbent, Neisser, journals.The 1970s.Later developments and criticisms.
25 Early BeginningsSome (e.g. Neisser, 1967) regard Sir Frederick Bartlett as a forerunner of cognitive psychology. He was based in Cambridge Psychological Laboratory.Before Bartlett the study of memory had been strongly influenced by Ebbinghaus, who looked at memory for nonsense syllables (e.g. guk, lif).
26 Early BeginningsBut Barlett wanted to be more naturalistic. Perhaps being well away from the influence of the American behaviorists, he felt relatively unfettered in what he could study.“Remembering” was book he published in 1932 looking at memory for stories and pictures. Participants had to recall “war of the ghosts” again and again. It got simplified in successive recalls.
27 Early BeginningsIn other expts one person’s recall was given to another and that was passed on, and so on. This serial reproduction was like the party game of “Chinese whispers” and produced the same result.Found: “condensation” involving the compression of information leaving out the irrelevant parts; “elaboration” where we add in extra bits that would be plausible, but weren’t actually included.Suggested: we have a “schema (-mata, pl) of what we’re listening to (ie. we have a mental model or skeleton). This schema is retrieved when we recall. Irrelevant details may not be retrieved. Recall is a reconstructive process, where the details are generated from the original skeleton, or schema.
28 Early BeginningsIn an experiment on the concept of schema Brewer and Treyens (1981) had participants wait in an academic’s study. Then they were called into another room and asked to describe the contents of the room they’d been waiting in. Several people recalled there being books in the room, when in fact the room had had no books in it. Thus they had reconstructed from their schemata what the room should have looked like.
29 Early BeginningsProblems with such work are to do with judging detail vs. schema is a matter of judgementBartlett also found evidence of emotional similarities in stories. This resulted in connections from one story to another. Details would thus pass from one story to another.
30 Early BeginningsIn more recent times, schema is called “frame of reference”. This is the set of beliefs about a topic.When recounting an event, you incorporate what you believe to be relevant to the frame of reference.When reading on a topic, you incorporate your frame of reference, into your interpretation of what you are reading.
31 Early BeginningsExperiments in Cognitive Psychology started mainly after WW2.Initially on “information processing”. We input information, process and store it. But there were several influences.
32 Background influences to development of Cognitive Science: computing Alan Turing ( ) was a British mathematician who committed suicide in his early 40s (see the web). He developed the idea of a simple machine (later called a “Turing machine”). This read a symbol, performed a simple operation on it and then wrote the answer back.
33 Background influences to development of Cognitive Science Symbols can be combined using a set of rules. This means that they can be used to perform deductive reasoning.A Turing machine could potentially perform a set of procedures to produce the solution to a problem. These procedures are known as “algorithms”.Turing showed that a binary code (1s and 0s) could be used to perform in combination very complex programs.
34 Background influences to development of Cognitive Science ‘Turing machine test’. A person converses with computer. But responses via this computer are actually from a computer or a person. They have to try to guess which is which. Turing thought that should be possible to develop so that the person would be only at chance level. Influential – human thought could be mimicked.John von Neumann: introduced notion of storage of program within memory.
35 Cybernetics & WeinerNorbert Weiner, mathematical prodigy, at MIT in 30s and 40s, worked on servomechanisms that guided missiles. Feedback and self-regularisation.Give feedback and a machine adjusts performance. They are purposeful.He wrote “Cybernetics” in He was interesting because he linked the human nervous system with the developing computer.
36 Neuronal modellingMcCulloch and Pitts (1943): looked at how nerve cell operates and connects to other nerve cells. A nerve cell firing could be viewed as all-or-none.Given the interconnections between cells, there could be a set of propositional statements coded in the network.
37 Neuronal modellingThe Turing machine could mimic networks, or else, produce abstract programs that describe mental processes.Hubel and Weisel (1962) later examined the firing of individual cells in the visual cortex of cats demonstrating firing to limited visual features.
38 Development of neuropsychology WW1 & WW2: brain damage due to shrapnel and missiles.
39 Development of neuropsychology Alexander Luria in Russia worked on brain-injured patients. Feeling that the time had come to investigate the mind more thoroughly. It was time to take a new direction from behaviorism. Many were impatient.
40 EthologyLorenz and Tinbergen observed animals in natural habitats. (Nobel prize for both in 1973.)Developed in 30s and 40s.The movement led to looking at more natural settings for humans as well.
41 Information theory Shannon and Weaver developed this in 40s. Concerned with coding, transmission, storage and retrieval and decoding of information.
42 Information theoryOne aspect of the theory was that text varied in the surprise value in its information. For instance, a headline “Prime minister killed” would generate a shock value because it would be very unexpected. However, “Prime minister opens toy factory” would not surprise.This can be explained in terms of chance. The odds of a really shocking event are usually much lower. It is a rare occurrence.
43 Information theoryIn experimental terms this could affect decision-making. If there is a choice between 2 alternatives, this is relatively easy. But if there are 4 alternatives involved, the chances of any light occurring is less, compared with when only 2 alternatives. It has been found that we tend to slow down when the event is less expected. Information theorists proposed that 2 alternatives involved 1 “bit” of information, 4 = 2 bits and 8 = 3 bits. Bits were equivalent to decisions.
45 Other important considerations The “Hixon Symposium” 1948: meeting of a group of eminent scientists from several disciplines, which proved a pivotal point.Important paper by Karl Lashley who challenged the behaviorists. The behaviorists had advocated study of only observable behaviour. But this excluded areas such as problem solving, practical skills, imagery and language.
46 Other important considerations Karl Lashley had suggested the behaviorist theory of associative stimulus-response chains could not work for fast motor sequences, as when playing music. There would not be enough time for feedback.Lashley proposed that the nervous system was always active and arranged in a hierarchy. The centre of the system determined control. Lashley’s paper, which was a substantial challenge to current thought, was very well received.
47 The early years of the cognitive science revolution Allan Newell and Herbert Simon: the first proof of a theorem from a computer program alone.Naom Chomsky developing his approaches to grammar and linguistic transformations.
48 The early years of the cognitive science revolution Miller (1956): important paper on the human memory and its limited capacity. Our memory of phonemes, numbers, words, or whatever unit seemed to change at about 7 items, plus or minus 2. This was the point beyond which errors occurred.
49 The early years of the cognitive science revolution Miller brought together different studies and combined in one simple concept. It also bridged with information theory. This limit was not limited just to the auditory system.Hilary Putnam suggested an interesting distinction between computer programs, lists of statements, and the wiring of computers. Similarly, one can study neural networks, analogous to wiring. Patterns of thought would be analogous to the computer programs.
50 The early years of the cognitive science revolution There was early cognitive work in selective attention such as by Broadbent and Cherry. In the UK, the influence of the behaviorists was not so strong.Early on the emerging discipline was known as “information processing”. This emphasised link between computer science and information theory.Neisser (1967) used the term “cognitive psychology” in his book. This expanded horizons to areas such as problem solving. He considered human cognition to be about the continual analysis and synthesis of information from the moment light reached the retina.
51 The early years of the cognitive science revolution Neisser’s book was tremendously influential at this time. He acknowledged the contributions of information theorists and computer scientists, but pointed out their limitations. E.g. bits were relevant to telephones, but not to attention within a human system. Computer programs (at that time) were too simple.
52 The early years of the cognitive science revolution New journals were created: Cognitive Psychology (1969), Cognition (1972) and Memory and Cognition (1973). Then textbooks on Cognitive Psychology followed. Later Applied Cognitive Psychology, edited in this department by Graham Davies.
53 By the 1970sThere were by now a very substantial number of papers being published in these new areas driven by a consensual view of mechanistic explanations of cognition.The Sloan foundation, a NY based private foundation decided to invest $15M into the young discipline.
54 By the 1970s: SternbergSaul Sternberg’s classic experiments (1966-9): Participants shown series of nos., each for 1.2 s. E.g. given and then they were given probe no. (e.g. 5) and had to say if present in the set of numbers in their STM. Each trial gave them a new set with a different size of 1-6 items. See fig for results.
55 By the 1970s: SternbergSternberg found that RT increased with set size. Processing rate was 38 msec/item. Also no difference in slope for the ‘yes’ or ‘no’ items.Strange result as suggested scanning is serial and exhaustive rather than self-terminating.
56 By the 1970s: SternbergOne would expect that when a “Y” required that when found S would immediately make a response. If this had happened the slope would have been half that for the “N” responses. For the “N” responses, all items would have to be scanned.But this is not what Sternberg got. He could conclude that scanning STS is serial and that it is exhaustive.
57 By the 1970s: SternbergSimilar results found for faces, colours and words with a different slope for different types of items. Differences in children vs. adults.Sternberg proposed: encoding the stimuli, memory search to find match, response selection (Y or N) and then response execution. He assumed these stages each took an added amount of time of the RT.However, the foundations of such experiments began to shake.In the case of Sternberg, his experiments can be also be explained by parallel processing. Variations in the paradigm produced challenges to his model.
58 By the 1970sIf an item is repeated (e.g ), RTs to it (3 in this case) are shorter suggesting other influences.People became increasingly sceptical. The models were elegant, but did not stand up to challenge.Also, this kind of work did not seem to be “ecologically valid”. There was a drift away from these types of experiments.
59 A later development: connectionism Early work in Cognitive Science had not worried particularly about the biological origin of the mind. There were later seen to be limits in the computer as a serial processor.
60 A later development: connectionism The connectionist approach (Rumelhart & McClelland, 1982) that was subsequently developing suggested thousands of connections between hundreds of units working in a parallel manner.The numbers were limited simply because it would take far too long to run proper simulations in proportion to the no. of connections in the brain. The simulations are laboriously done on a computer in serial, but they actually simulate units as if they have parallel connections.
61 A later development: connectionism Processing was now about the changing weightings of connections among the units. It seems to have been an approach that has produced new solutions in the areas of perception and thought.Some suggest a distinction between the “orthodox cognitive psychologist” (OCP) and the “cognitive scientist”.The OCP is more interested in the intellectual side and is not concerned with biology.
62 Criticisms of the cognitive scientific approach An important concept is that the mind is considered to be mechanistic. That is, a mechanical system that operates by physical laws.(Remember the historical concept of mechanism we examined under behaviorism?)In practice, this means that a computational system is able to simulate the mind. It leads to the idea that rationality and intention is essentially mechanistic. Many cognitive scientists believe that this can be the only conception of mind.
63 Criticisms of Cognitive Psychology Costall and Still (1991): Cognition is too restricted to the individual and to the intellect. The mind is seen as a series of operations that is worthy of study. Social aspects are largely ignored. There is however “cognitive social psychology” which uses similar tools to the cognitive scientist. This examines social attitudes and stereotypes.What seems to be missing from cognitive social psychology is the concept that social influences help to form the human mind. The social constructionalists believe that mind is constructed foremost from the influences of society. Berger and Luckmann’s (1967) book was influential in this area.
64 Criticisms of the cognitive scientific approach In a controversial thought experiment, Hilary Putnam (1981) imagines a “brain in a vat”. It is isolated and gets inputs from a computer connected to its nerve endings. The thought processes in this brain are hallucinations even though they are the same as those of a normal person using their senses to examine their environment. Thus a mental state alone is not enough for seeing and understanding. We are affected by what is in our environment.
65 Criticisms of the cognitive scientific approach Meaning is partly social. For instance, I may use words such as “beech” and “elm”, even though I may be hazy about what these trees are actually like. I rely on knowledge of others, particularly experts, to differentiate these two categories of tree. I am relying on a linguistic community.Another criticism of “orthodox cognitive psychology” is that it focuses on higher mental functions and has disregarded the body.
66 Criticisms of the cognitive scientific approach This is perhaps historically partly due to the rejection of behaviorism, which advocated observing the responses of the body.Thus in cognitive terms modelling the operation of the lexicon should be little different from modelling the skills involved in piano playing. But these perform very different functions.But our body is important. Eg. for perception to work we move our eyes, we grasp and we walk around. We need innumerable skills that cannot be spelled out in terms of propositional knowledge. Mind is not locked in the head, it works in a culturally formed environment.
67 Criticisms of the cognitive scientific approach After the tremendous excitement of the “cognitive revolution”, there was an experience of something of a downcycle. Neisser 10 years later in (1976) was critical of the computer metaphor in cognition, as well as the indifference to cultural influences.He disliked what he called the “mechanistic information processing models”. For instance, in perception he wanted us to understand how we are able to see a stable world while we ourselves moved around it.
68 Criticisms of the cognitive scientific approach Glass, Holyoak and Santa (1979) state: “Cognitive Psychology is not getting anywhere; … in spite of our sophisticated methodology, we have not succeeded in making a substantial contribution toward the understanding of the human mind.” (p. ix).
69 Criticisms of the cognitive scientific approach Gardner (1985, p134) remarks that there was perhaps excessive excitement about the cognitive revolution. To him it is perhaps unsurprising that this has given way to a less ecstatic reaction. He doesn’t criticise experiments under artificial conditions, but these findings can be unstable, when the conditions are changed a little.Gardner’s own observation is that when a new interesting finding is reported, many experimenters then work hard to uncover its weaknesses. In the end, the finding is found wanting in some way. This gives the impression of advances going backwards rather than forwards.Gardner would like to see broader, more relevant problems tackled with the sophisticated methods that have been developed by cognitive psychologists.
70 Overview Early beginnings: Bartlett. Background influences: computing, cybernetics, information theory and war.Early part of cognitive revolution: Miller, Broadbent, Neisser, journals.The 1970s.Later developments and criticisms.