Properties of feature detectors for place of articulation

An experiment was conducted in order to determine whether the sensitivity of a detector tuned to place of articulation is reduced by selective adaptation. The basic stimuli were three syllables, [ba], [da], and [ga]. Each of these syllables was synthesized with F2 and F3 at nine levels of attenuation relative to F1, for a total of 27 stimulus tokens. The task of the subject was to indicate which of the three syllables was heard on each trial. As expected, prior to adaptation the identification of [ba] and [ga] (although not [da]) was a function of attenuation level, with performance systematically declining as F2 and F3 were attenuated. Adaptation with [ba] resulted in a depression of the [ba] response function and similarly, adaptation with [ga] resulted in a depression of the response function for [ga]. Thus after adaptation with a particular syllable, an increase in the critical energy (i.e., less F2−F3 attenuation) was required in order to yield a given level of performance on that syllable. These res...