Speech-production measures of speech perception: rapid shadowing of VCV syllables

Five listeners rapidly repeated ("shadowed") a random presentation of the vowel-consonant vowels (VCV's)/aba, apa, ama, aka, aga/. Initial vowel duration was varied to eliminate it as a temporal cue to the occurrence of the consonant. These shadowing, choice reaction times (RT's) were compared to simple RT's obtained when listeners always produced /aba/ or /ba/ to the same syllables. Both /aba/ and shadowing reactions were extremely fast (170 to 240 ms). Latency differences between the two tasks were attributable to differences in the point at which cues sufficient for responding were present. These results suggest that speech-perception decisions in shadowing are directly available to, and are perhaps made to occur at a point comparable to the consonantal release seen for the simple /aba/ responses. This result suggests that the motor organization required for a /ba/ response includes an implicit time interval appropriate for a consonantal closure.