SUSTAINED ATTENTION AND INTELLIGENCE

The sustained attention of retarded and nonretarded adults was assessed during two 60-min vigilance tests that differed in memory demand. Subjects compared visually presented digit sets that were separated by 3 or 6 s; consecutive matching digit sets served as the target event. A significant interaction between IQ and time period was obtained for target detection and detectability, p(A), measures; the performance of retarded subjects declined more rapidly during the latter stages of the vigil than did the performance of nonretarded subjects. Memory load had no effect on target detection, but the 6-s delay resulted in a significant increase in false alarm rate by both IQ groups. Intelligence-related differences in sustained attention appear to be related to the availability of attentional resources during a vigilance task. © 1990.