Explain how stimulus equivalence classes can be established. What implications does this type of human learning have for behavioural accounts of psychology?

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2001:  What is relational learning?  Evaluate the view that it is the human capacity for learning arbitrary relations that distinguishes their learning abilities from those of other species and underpins the development of language.

2002:  Explain how stimulus equivalence classes can be established.  What implications does this type of human learning have for behavioural accounts of psychology?

2003:  Explain how stimulus equivalence classes can be established.  What are the implications of the findings, to date, that this type of learning occurs in humans but not in other species?

You are watching an annoying television programme and your friend asks you to turn the station over, if you are in a compliant mood, you will immediately lift the remote control and turn over.  Alternatively, your friend could sigh loudly and look disdainfully in the general direction of the television; again you comply by switching the channel over.  Or, your friend could complain loudly about the programme you are watching until you give in and turn over.  The request to turn the television over, disdainful looks at the television and complaints about the programme are examples of physically different discriminative stimuli that serve the same purpose – that is, they are ‘functionally equivalent’.  Even though none of the above stimuli share the same physical characteristics, they still serve the same function.  We could assume that lifting the remote control and turning the television over has been reinforced under all conditions.  This would be an extremely laborious and inefficient way to learn.  

‘Matching to sample’ training is the discrimination training procedure commonly employed to investigate ‘stimulus equivalence’ and ‘equivalence classes’.  These experiments are usually carried out using verbally competent human participants.  For convenience sake stimuli, usually nonsense syllables or random shapes are presented on a computer screen.  This type of stimuli is used because they have no significance to the participant prior to training.  The random shapes or nonsense syllables are labelled by the experimenter in such a way that s/he can define the ‘correct’ response and keep track of the training procedure involved.  Labels used in this example are A1, A2, A3, B1, B2, B3, C1, C2 and C3.  A ‘sample stimuls’, in this case A1, will be presented at the top, centre of the screen and three ‘comparison stimuli’ (B1, B2 and B3) are presented at the bottom of the screen. The sample stimulus, A1, must be matched to the correct comparison stimulus, B1, by selecting the corresponding response key.

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In the first phase of the experiment participants are trained to match (typically three) sample stimuli to the same number of comparison stimuli e.g. A1 to B1, A2 to B2 and A3 to B3.  It is presumed that automatic feedback by the computer i.e. ‘Correct’ or ‘Incorrect’ acts as reinforcement for correct responses.  Across trials sample stimuli varies (A1, A2 or A3) but the comparison stimuli appears in different locations so that position gives no clue to correct responses.  Once performance criterion is achieved – normally correct responses on more than 90% of a ...

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