Hemispheric asymmetries for gap detection depend on noise type.

Studies of temporal processing asymmetries in the auditory modality have not produced consistent results. Some investigators have found a left hemisphere advantage, but others have failed to replicate this result. The present experiment investigated the possibility that differing properties of the noise employed between these experiments could be responsible for the conflicting results. Short bursts (300 ms) of white or brown noise were delivered monaurally to 42 participants. Half of the stimuli contained 3-5 ms gaps of silence. A right ear (left hemisphere) advantage in accuracy was observed in the white noise condition, but there was no such difference in the brown noise condition. This result demonstrates that the different acoustic properties of the stimuli between experiments can account for some of the discrepancies in their findings, and supports the position that the left hemisphere is superior at processing rapid temporal changes.