ASA 127th Meeting M.I.T. 1994 June 6-10

4pPP6. Within- and across-channel processes in modulation detection interference.

Div. Otolaryngol./Head & Neck Surgery, Univ. North Carolina, Chapel Hill, NC 27599-7070

Modulation detection interference (MDI) was measured using sinusoidally modulated (10 Hz) tones. In order to assess the relative influences of within- and across-channel processes, the carrier frequency of the target was held constant at 993 Hz, while the carrier frequency of the interferer was either 450, 596, 788, 1250, 1654, 2188, 2895, or 3828 Hz. The interferer carrier was presented either to the same ear as the target carrier, or to the ear contralateral to the target. In addition, the interferer carrier was either gated synchronously with the target carrier, or present continuously. Although individual differences were observed, substantial MDI occurred in the contralateral as well as the monaural gated-interferer conditions. While most subjects showed increasing interference as the monaural-interferer carrier frequency approached the carrier frequency of the target, some subjects also demonstrated increasing MDI as the interferer carrier approached the target carrier in the gated contralateral-interferer condition.