The purpose of this study was to investigate the retrieval speed of mental retardates in a constrained recall task. Eighteen retardates (Mean CA=17:10, Mean MA=9:1, Mean IQ=51) and eighteen equal MA non-retardates (MeanCA=9:3, Mean MA=9:11, Mean IQ=108) were asked to learn a list of twelve pictures from three taxonomic categories. After all pictures were presented in category block, subjects were required to recall them in a constrained method. Dependent variables were as follows: (1) Numbers of recalled items within categories; (2) RT, the time interval between experimenter's category instraction and subjects'first recall response; (3) WCI, the time interval between a recall response and the next one. The main results were: RT of retardates was longer than that of nonretardates; also, WCI showed similar results. Such results suggested that one of the cognitive deficits of retardates was in the difficulty of category access.
View full abstract