Sinusoidal plucks and bows are not categorically perceived,either

Cutting and Rosner (Perception & Psychophysics, 1974,16, 564–570) reported that two acoustic nonspeech continua varying in rise time were categorically perceived. We have already shown (Rosen & Howell,Perception & Psychophysics, 1981,30, 156–168) that the reason their sawtooth continuum was perceived in such a way, and in particular why it exhibited a midcontinuum peak in the discrimination function, was entirely due to the stimuli not having the intended rise times. The other nonspeech continuum that varied in rise time and was reported to be categorically perceived used a sinusoidal carrier. Although the labeling functions obtained were not as sharp as those obtained with sawtooth stimuli, the characteristic midcontinuum discrimination peak was found. We generated such a set of sinusoidal stimuli and found no evidence of categorical perception. Just as we have previously found for sawtooth stimuli, discrimination is best at the short rise-time end of the continuum and decreases monotonically with increasing rise time.