Nonselective read-out from iconic memory in normal, borderline and retarded adolescents

The hypothesis that retarded individuals read-out information from iconic memory at a slower rate, relative to their CA matched peers, was tested. Three IQ groups (normal, borderline and retarded) were selected with 10 subjects in each group. A tachistoscope presented a stimulus array and a post-stimulus cue for 100 msec. each, separated by a variable interstimulus interval (ISI). This stimulus array consisted of 10 letters arranged on two horizontal rows. The post-stimulus cue was a circle which surrounded the position of the correct letter. Nine ISIs were used and ranged from −100 (cue before array) to 500 msec. A 3 × 9 repeated-measures analysis of variance revealed non-significant effects for IQ and the IQ × ISI interaction. A significant effect was found for ISIs (p < .01) which reflected reduced performance at the intermediate ISIs for all intelligence groups. The hypothesis of a read-out deficit in the retarded was not supported. The present findings were discussed in relation to previous research which supported a read-out deficit in the retarded.