Processing two dimensions of nonspeech stimuli: the auditory-phonetic distinction reconsidered

Nonspeech stimuli were varied along two dimensions--intensity and rise time. In a series of speeded classification tasks, subjected were asked to identify the stimuli in terms of one of these dimensions. Identification time for the dimension of rise time increased when there was irrelevant variation in intensity; however, identification of intensity was unaffected by irrelevant variation in rise time. When the two dimensions varied redundantly, identification time decreased. This pattern of results is virtually identical to that obtained previously for stimuli that vary along a linguistic and a nonlinguistic dimension. The present data, taken together with those from other studies using the same stimuli, suggest that the mechanisms underlying the auditory-phonetic distinction should be reconsidered. The results are also discussed in terms of general models of multidimensional information processing.