Capacity of Severely Subnormal Children with Relation to the Non-Additivity of Cues Effect and to Discrimination Difficulty

Abstract

The phenomenon of non-additivity of cues has been shown to exist in the learning of various types of discriminations by rats (Sutherland and Mackintosh, 1964; Sutherland and Holgate, 1966). In the present study severely subnormal children were trained to discriminate stimuli differing along two dimensions, both dimensions being relevant to the discrimination. Having learned to criterion they were then transfer-tested on each of the dimensions presented separately. Results showed both that subjects tended to respond in terms of dimensions and also that slow learners tended to learn the discrimination in terms of only one dimension whereas faster learners tended to learn about both dimensions. In a further study it was found that the more difficult the discrimination to be made the more the subjects tended to learn it in terms of only one of the two possible relevant dimensions. Some varying interpretations of the concepts of attention and capacity and their value and precision in explaining these results are considered.

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