Storage and decay characteristics of nonattended auditory stimuli.

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Abstract
Four Ss were individually run through 20 2-hr. sessions during which their primary task was to read a novel of their own choosing. At random intervals during the session a 1,000-cycle, 1/2-sec. tone of low intensity occurred. At delays ranging from 0 to 10.5 sec. following onset of the tone an alerting stimulus (reading lamp turned off) occurred. At the alerting stimulus S had been instructed to interrupt his reading and make a judgment as to whether the tone had occurred during the immediately preceding 10-15 sec. period. Sessions were run under a high and low condition of irrelevant noise. Detection of the signal was found to be a decay function of the delay of the alerting stimulus out to delays of 10.5 sec. Four Ss were run in a 2nd experiment to determine whether the detection at 10.5 sec. delay represented the spontaneous rate for detection without an alerting stimulus. Significant memory at 10.5 sec. delay over the spontaneous detection rate was found. No effect of level of extraneous background noise was found. Implications for models of attention were considered.