J. Devin McAuley
Dept. of Comput. Sci., Cognitive Sci. Program, Indiana Univ., Bloomington, IN 47405
Gary R. Kidd
Indiana Univ., Bloomington, IN 47505
Listeners' abilities to detect changes in tempo were investigated with two- and four-tone isochronous sequences with interonset intervals (IOI) of 100, 400, 700, and 1000 ms. Separate thresholds were measured for increases and decreases in tempo using an adaptive-tracking procedure. On each trial a standard pattern was followed by two comparison patterns, one of which was faster or slower than the standard. Listeners judged which comparison pattern was different from the standard. Consistent with previous studies of tempo discrimination, thresholds were found to be lower with four-tone sequences than with two-tone sequences, especially at the faster tempos. However, at the fastest tempos, listeners showed greater sensitivity to increases than to decreases in tempo, while the reverse was true at the slower tempos. The crossover point occurred at an IOI between 400 and 700 ms. The findings are consistent with the predictions of an entrainment model [J. D. McAuley, J. Acoust. Soc. Am. 95, 2966 (A) (1994)] in which tempo sensitivity is reflected by the degree to which a system of adaptive oscillators is entrained by the rhythm of a stimulus pattern. [Work supported by NIMH and NIDCD.]