Choice reaction-time of natural speech as affected by adaptation

Ss judged a pair of consonants as "same" or "different." There were 15 consonant pairs each judged by a separate group of 10 college students. For 5 of the pairs, judgments were preceded by an adaptation exposure to one of the consonants in the pair, at the rate of 1/sec for 2 min. The choice reaction time (CRT) was noted in msec for every response of each S. "Same" judgments were uniformly faster. Some support was given for a differential mediation of transient and steady-state acoustic speech cues in short-term storage, as demonstrated by a tendency for fricative consonants to yield faster CRTs than stop consonants. A post-adaptation increase in CRT was demonstrated; however, this effect was general and not selective for the repeated consonant. The implications of this research for theories of speech perception and for further investigation are (1) that the CRT procedure is appropriate for making inferences about the temporal aspects of the acoustic speech storage mechanism, (2) that the CRT and adaptation procedures can be combined to make judgments regarding the neural mechanisms of speech perception, and (3) that there are different memory storage modes for different types of speech information.