Effective Onset Duration of Auditory Stimuli

Tobias, Jerry V.; Schubert, Earl D.

doi:10.1121/1.1907665

Cited by 57 publications

(39 citation statements)

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“…These interaural time differences arise because there is distance between the two ears, so sounds reach the ear nearest to the sound source first and the other ear later (1,2). For sound durations greater than about 150 ms, listeners are far more sensitive to differences at the two ears in the ongoing fine time structure of the sound than in the onset time of the sound (3,4). These ongoing time differences are equivalent to interaural phase differences (IPDs) for tonal stimuli, but will be referred to as ITDs in this paper.…”

mentioning

confidence: 99%

Different patterns of human discrimination learning for two interaural cues to sound-source location

Wright

Fitzgerald²

2001

Proc. Natl. Acad. Sci. U.S.A.

145

144

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Two of the primary cues used to localize the sources of sounds are interaural level differences (ILDs) and interaural time differences (ITDs). We conducted two experiments to explore how practice affects the human discrimination of values of ILDs and ongoing ITDs presented over headphones. We measured discrimination thresholds of 13 to 32 naive listeners in a variety of conditions during a pretest and again, 2 weeks later, during a posttest. Between those two tests, we trained a subset of listeners 1 h per day for 9 days on a single ILD or ITD condition. Listeners improved on both ILD and ITD discrimination. Improvement was initially rapid for both cue types and appeared to generalize broadly across conditions, indicating conceptual or procedural learning. A subsequent slower-improvement stage, which occurred solely for the ILD cue, only affected conditions with the trained stimulus frequency, suggesting that stimulus processing had fundamentally changed. These different learning patterns indicate that practice affects the attention to, or low-level encoding of, ILDs and ITDs at sites at which the two cue types are processed separately. Thus, these data reveal differences in the effect of practice on ILD and ITD discrimination, and provide insight into the encoding of these two cues to sound-source location in humans.A listener who determines the position of a singing bird concealed among tree leaves, a jet passing overhead hidden by clouds, or a car approaching from behind, does so by using several auditory cues to the location of sound sources. Here we report the results of two investigations into how practice influences the ability of human listeners to discriminate small differences in each of two of these cues, interaural level differences (ILDs) and interaural time differences (ITDs).In humans, the horizontal location, or azimuth, of sound sources is computed from differences in the information that arrives at the two ears. At frequencies above about 1.5 kHz, listeners determine sound azimuth primarily from sensitivity to differences in sound level at the two ears. These interaural level differences occur because the head forms a sound barrier between the two ears, so sounds are attenuated at the ear farthest from the source relative to the ear nearest to the source (1, 2). At frequencies below about 1.5 kHz, listeners determine sound azimuth primarily from sensitivity to differences in the arrival time of the sound at the two ears. These interaural time differences arise because there is distance between the two ears, so sounds reach the ear nearest to the sound source first and the other ear later (1, 2). For sound durations greater than about 150 ms, listeners are far more sensitive to differences at the two ears in the ongoing fine time structure of the sound than in the onset time of the sound (3, 4). These ongoing time differences are equivalent to interaural phase differences (IPDs) for tonal stimuli, but will be referred to as ITDs in this paper.There have been many investigations into whether huma...

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mentioning

confidence: 99%

Different patterns of human discrimination learning for two interaural cues to sound-source location

Wright

Fitzgerald²

2001

Proc. Natl. Acad. Sci. U.S.A.

145

144

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“…The affected modulation rates and other characteristics of this onset dominance ͑cf. Freyman et al, 1997͒ call to mind a range of closely related binaural phenomena including binaural adaptation ͑Hafter and Dye, 1983; Hafter, 1997͒, the precedence effect ͑Wallach et al, 1949͒, and the Franssen effect ͑Franssen, 1962; Hartmann and Rakerd, 1989͒. The relative contributions of onset and ongoing envelope ITD have been assessed using a variety of methods ͑Tobias and Schubert, 1959;Abel and Kunov, 1983;Buell et al, 1991;Saberi and Perrott, 1995;Buell et al, 2008͒. A particularly illuminating approach has been to measure the relative sensitivity of listeners' localization responses to alterations of the spatial cues contained in each temporal portion of the stimulus ͑e.g., each click in a train of clicks͒.…”

Section: Introductionmentioning

confidence: 99%

A recency effect in sound localization?

Stecker

Hafter

2009

The Journal of the Acoustical Society of America

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In a free-field pointing task, listeners localized trains of 4-32 spatially distributed Gabor clicks ͑narrowband impulses͒ centered at 4-kHz carrier frequency and repeating at an interval of 5 ms. Multiple regression coefficients estimated the perceptual "weight" applied to each click in a train during location judgments. Temporal weighting functions obtained in this way exhibited two key features: onset dominance, as evidenced by high weight on the initial click, and "upweighting" of late-arriving sound, as evidenced by weights that gradually increased over the duration of each click-train. Across all tested click-train durations, and despite randomly varying the durations from trial to trial, the greatest post-onset weights were consistently found for clicks at or near the offset. The results imply a special importance of late-arriving sound rather than feedforward recovery from onset dominance, and are broadly consistent with recency effects resulting from temporal integration.

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“…However, the present experiment demonstrates that when speech and noise which have similar gross spectral and temporal characteristics are presented REFERENCES gated, thus providing three sets of potential cues: onset, offset, and ongoing time differences. Because of the duration of the intervals, and the data reported by Perott and Baars (1974), Tobias and Schubert (1959), and Yost (1977), it was felt that this arrangement would not yield different results than if only ongoing time differences were present. To determine if the presence of multiple cues did enhance performance for these signals at the durations employed, a separate experiment was conducted in which only the microstructure of a 500-Hz tone and a speech stimulus were delayed.…”

Section: Resultsmentioning

confidence: 99%