Differences in American English, Spanish, and monkey perception of the say-stay trading relation.

An interesting phenomenon in human speech perception is the trading relation, in which two different acoustic cues both signal the same phonetic percept. The present study compared American English, Spanish, and monkey listeners in their perception of the trading relation between gap duration and F1 transition onset frequency in a synthetic say-stay continuum. For all the subjects, increased gap duration caused perception to change from say to stay; however, subjects differed in the extent to which the F1 cue traded with gap duration. For American English listeners, a change from a low to a high F1 onset caused a phoneme boundary shift of 26 msec toward shorter gap durations, indicating a strong trading relation. For Spanish listeners, the shift was significantly smaller at 13.7 msec, indicating a weaker trading relation. For monkeys, there was no shift at all, indicating no trading relation. These results provide evidence that the say-stay trading relation is dependent on perceptual learning from linguistic exposure.