F0 discrimination interference: Effects of resolved tone complexes and noise on fundamental frequency discrimination of unresolved complex tones

Abstract

F0 discrimination of a 400-ms complex tone with only unresolved components (‘‘target’’) was investigated in the absence and presence of a synchronously gated resolved complex tone (‘‘interferer’’). The target and the interferer were bandpass filtered from 1375–15<th>000 Hz and 125–625 Hz, respectively. In a 2I-2AFC task, listeners indicated the interval containing the target with the higher pitch. The nominal F0 of the target was 88 Hz; that of the interferer was constant across the two intervals and was either 88 Hz or increased by various amounts. Although the target and interferer were in well-separated frequency regions, performance (percent correct) dropped by about 16% when the interferer’s F0 was 88 Hz. The impairment was halved when the interferer’s F0 was 10% higher than that of the target, and almost eliminated when it was 30% higher. Increasing the level of a 1375-Hz low-pass-filtered noise, gated synchronously with the target and the interferer (F0 equaled 88 Hz), improved performance, further demonstrating that the deterioration produced by the resolved complex was not due to peripheral masking. The results are consistent with a form of across-frequency interference at the level of pitch perception. [Work supported by EPSRC Grant GR/R65794/01.]