Effects of Warning Signal Intensity, Reaction Signal Intensity, Preparatory Interval, and Temporal Uncertainty on Reaction Times of Mental Defectives

Abstract

The reaction times of mentally defective Ss were studied in relation to variations in reaction signal intensity (15 or 65 dB above threshold), warning signal intensity (15, 40, or 65 dB above threshold), preparatory interval (2, 4, 7.5, or 15 sec), and temporal uncertainty. The warning signal was a 1000 cps pure tone to the left ear; the reaction signal was a 1000 cps tone to the right ear. The results revealed that each increment in warning signal intensity produced reliably longer reaction times. In addition, an interaction was observed involving preparatory interval and temporal uncertainty. Under conditions of maximum objective time certainty the shortest (2 sec.) interval was associated with the fastest responses. When temporal uncertainty was maximized, the shortest interval produced the slowest re-sponses. Contextual factors were implicated in this effect.