Aspects of cognitive processing in severely retarded adults
The aim of this thesis was to investigate some aspects of attention and discriminative learning in severely retarded adults, in particular to establish whether a one-look model of selective attention or a multiple-look model of selective attention is more applicable to these subjects. The subjects were 63 adult trainees from two adult training centres, and 46 children from three local schools. The severely retarded adults were in the M.A. range of 2 years, 11 months to 6 years, 0 months. The school children were aged from 3 years, 2 months to 6 years, 0 months. Fisher et al. (1969) and Zeeman (1973) suggest that the superiority of high M.A. retardates over low M.A. retardates on component testing may reflect either a breadth of attention limited to one dimension in low M.A. retardates or a rapid rate of decay, in short term memory. The breadth of attention of low. M.A. retardates was assessed in the present thesis by presenting the subjects with matching problems and component test problems. Results indicated strongly that low M.A. retarded subjects could attend to at least two component dimensions simultaneously. Short term memory decay was shown to be greater for low M.A. retarded subjects than for relatively high M.A. retarded subjects. Both groups of retarded subjects showed greater decay than children of comparable M.A. Associated findings were that there were no differences on a cancelling task between retarded adults and children of equivalent M.A. On an incidental learning task, retarded adults were weaker than children of comparable M.A. These results were interpreted as providing evidence of multiple looking in low M.A. retardates. They were also taken as providing evidence in support of the hypothesis that retention may be related to intelligence. It was suggested that future research should focus on the training of strategies to enable severely retarded individuals to reach the limit of their breadth of attention and retention capacities.