Ear asymmetry and the temporal uncertainty of signals in sustained attention

Subjects listened for increments in the duration of recurrent white noise pulses delivered to either the left or the right ear during a 1-h vigilance session. The temporal uncertainty of critical signal occurrences was varied by use of signal densities of 24, 48, and 96 signals/hour. Response times to signal detections increased as a function of an information measure of the temporal uncertainty of signals with a markedly stronger effect from left-ear presentation. Thus, a functional lateral asymmetry in the cortical processing of temporal information in this type of task was indicated.