Effect of temporal separation on tone-sequence discrimination in monkeys.

Perception of auditory spectral-temporal patterns was examined in two Japanese monkeys. The stimuli used were pairs of pure tones of different frequencies that were presented sequentially. The monkeys were required to discriminate whether the frequency of the second tone was higher or lower than the first tone. The performances of the monkeys deteriorated when a temporal gap (i.e., silence) was inserted between the component tones. A comparison experiment did not show such effects in human participants. The results suggested that monkeys use frequency transitions for tone-sequence discrimination, and that local characters are more dominant discrimination cues in monkeys than in humans. Copyright 2002 Elsevier Science B.V.