“Temporal masking” in discrimination of tone glides

Abstract

Difference limens for tone-glide stimuli are reported to be greater when the glide precedes a contiguous 200-ms fixed-frequency segment than when the glide follows a contiguous fixed-frequency segment [M. J. Collins and H. Stromberg, J. Acoust. Soc. Am. 66, Suppl. 1, S9 (1979)]. The present study was carried out to test the hypothesis that the effect was due, in part, to “temporal masking” of the tone glide by the fixed-frequency segment. Six normal hearing subjects served as listeners. Reference stimuli consisted of 30-ms glide segments, preceded or followed by fixed-frequency (2200 Hz) segments of varied duration. Endpoint frequencies of the reference glide segments were 1680, 2200, and 2710 Hz for both glide-preceding and glide-following conditions. Results indicated that, in general, a greater amount of “masking” was imposed by fixed-frequency segments which preceded glides than by fixed-frequency segments which followed glides. This was particularly evident for the conditions which involved discrimination between no glide and some glide (2200-Hz endpoint frequency): essentially no “forward” masking was observed with significant “backward” masking for the comparable glide-preceding condition. [Work supported by NIH.]