Lateralization of Filtered Clicks

Lateralization of brief clicks was studied while the frequency content of the clicks was altered by filtering. The subject was asked to discriminate a centered image, a pair of identical clicks that arrived simultaneously at the two headphones, from a displaced image, a pair of identical clicks in which the click to the left ear was slightly delayed. The discrimination of the lateral position deteriorated as the clicks were high-pass filtered beyond 1500 Hz and was largely unaffected by low-pass filtering. Masking with high-pass and low-pass noise showed that low-pass noise severely disrupted the lateralization of the high-pass clicks, but the high-pass noise produced no disruption of the lateralization of the low-pass clicks. Our results suggest that the discrimination of lateral position depends largely on the low-frequency content of the click and thus, presumably, on the apical end of cochlear partition.