短音のピッチ認識に及ぼす後続音の効果に関する検討

抄録

Interference effects of a trailing tone on recognition for pitch of a brief tonal signal(S_c)presented earlier in time are investigated. In the experiments reported here, all of the experimental conditions are varied randomly, and a same-different procedure is employed. The proportion of correct responses is measured as a function of the silent intertone interval(&Irtri;t)between the S_c and the trailing tone, the trailing tone duration, and the frequency separation between the signal and trailing tone. Furthermore, the temporal growth course of recognition accuracy of S_c are discussed. The d'value of signal detection theory is employed as a measure of the recognition accuracy. The results obtained are as follows:(1)The percent correct recognition for pitch improves with increases in &Irtri;t, but become dull for the long &Irtri;t of about150msec. (2)The interference produced by the trailing tone is independent of its duration. (3)The interference produced by the contralateral trailing tone is as effective as the ipsilateral one. (4)The interference produved by the trailing tone seems to vary with the frequency separation between the signal and tailing tone over200Hz(5)The improvement in the recognition accuracy of S_c can be well fitted with the equation a(t_p)=α{1-exp(-t_p/τ)}, where a(t_p)is the recognition accuracy of S_c, t_p is the presentation time including both the duration of S_c and &Irtri;t, α is a finite asymptote, and τis a time constant.