Anchoring and selective adaptation may affect different processing mechanisms

Abstract

Fifteen synthetic CV syllables varying perceptually from [di] through [ti] to [si] were used in an identification task. In the control condition each stimulus occurred equally often. In the anchoring conditions, one of the phonetic exemplars occurred more often than the other stimuli. For the [di] and [ti] anchor groups no consistent changes in identification were found. The [si] anchor group showed a significant shift of the [ti]-[si] category boundary toward the [si] endpoint. The [di]-[ti] boundary showed no systematic change after anchoring. A qualitatively different pattern of results were obtained using a similar set of stimuli in a selective adaptation paradigm [W. A. Ainsworth, Percept. Psychophys. 21, 365–370 (1977)]. Both [di] and [ti] adaptors caused shifts of both category boundaries in the direction of the adaptor while [si] had no systematic effects. It is possible that selective adaptation may affect channels of analysis sensitive to relative timing information. The effects of anchoring may be attributed to the differential availability of auditory memory for stop consonants and fricatives. [Work supported by NSF and NIMH.]