Objective and Subjective Psychophysical Measures of Auditory Stream Integration and Segregation

Abstract

The perceptual organization of sound sequences into auditory streams involves the integration of sounds into one stream and the segregation of sounds into separate streams. "Objective" psychophysical measures of auditory streaming can be obtained using behavioral tasks where performance is facilitated by segregation and hampered by integration, or vice versa. Traditionally, these two types of tasks have been tested in separate studies involving different listeners, procedures, and stimuli. Here, we tested subjects in two complementary temporal-gap discrimination tasks involving similar stimuli and procedures. One task was designed so that performance in it would be facilitated by perceptual integration; the other, so that performance would be facilitated by perceptual segregation. Thresholds were measured in both tasks under a wide range of conditions produced by varying three stimulus parameters known to influence stream formation: frequency separation, tone-presentation rate, and sequence length. In addition to these performancebased measures, subjective judgments of perceived segregation were collected in the same listeners under corresponding stimulus conditions. The patterns of results obtained in the two temporaldiscrimination tasks, and the relationships between thresholds and perceived-segregation judgments, were mostly consistent with the hypothesis that stream segregation helped performance in one task and impaired performance in the other task. The tasks and stimuli described here may prove useful in future behavioral or neurophysiological experiments, which seek to manipulate and measure neural correlates of auditory streaming while minimizing differences between the physical stimuli.

Stream segregation with high spatial acuity

“…It contrasts with other objective measures that test whether spatial cues can defeat efforts to fuse two sound streams (e.g., Stainsby et al, 2011). It also contrasts with subjective measures in which the listener is asked whether a sequence of sounds is heard as one or two streams (e.g., contrasted by Micheyl and Oxenham, 2010). We employed an objective task using non-verbal stimuli because we wanted to minimize top-down linguistic components of segregation and because we hoped eventually to relate the results to ongoing animal studies.…”

Fine frequency tuning in monkey auditory cortex and thalamus

“…These findings challenge the notion that the fine frequency tuning of auditory cortex is unique to human auditory cortex and that it is a de novo cortical property, suggesting that the broader tuning observed in previous animal studies may arise from the use of anesthesia during physiological recordings or from species differences. medial geniculate; thalamocortical dynamics; bandwidth; marmoset FINE-GRAINED REPRESENTATION of sound frequency is critical for sound segregation and recognition (Bregman 1990, p. 58 -68, 83-92, 642-654;Carlyon 1992;Micheyl and Oxenham 2010). The initial stages of auditory processing decompose sound signals into frequency bands that span approximately onequarter to one-seventh of an octave in the auditory nerve near threshold (see Table 1), which is the effective resolution of the input into the central auditory system.…”

Physiology, Psychoacoustics and Cognition in Normal and Impaired Hearing

“…It is also known that within-stream (within-pattern) comparisons are far easier to make than between stream comparisons; (e.g. Micheyl and Oxenham 2010)). Therefore, we hypothesized that if the standard pattern satisfied Gestalt grouping principles and could thus be more easily grouped, this would facilitate pattern comparisons, and that deviations within such patterns would be easier to detect.…”