Easy come, easy go: Examining the stability of lexically guided perceptual learning over time

Abstract

Listeners can use lexical information to accommodate ambiguity in speech input. Some evidence suggest that lexically guided perceptual learning persists over time. However, other evidence suggests that lexically guided perceptual learning attenuates throughout the test session, consistent with distributional learning that occurs given exposure to the test stimuli. Here we test the hypothesis that lexically guided and distributional learning may operate over different time scales. During exposure, listeners heard spectral energy ambiguous between /ʃ/ and /s/ in a lexically-biasing context. At test, listeners categorized tokens from an ashi-asi continuum. Test duration was manipulated between subjects to be either brief or long. Approximately 24 hours later, both groups completed a second test phase. The results to date show (1) robust lexically guided perceptual learning at the first test, (2) attenuation of learning for the long duration compared to the short duration test group at the first test, and (3) no robust evidence of lexically guided perceptual learning for either group at the second test. If these results hold in the full sample to be tested, then they would suggest that lexically guided perceptual learning is best characterized as dynamic adaption to recent input that dissipates within a day.