Auditory streaming and vertical localization: Interdependence of “what” and “where” decisions in audition

Abstract

When a sequence of two tones is presented over headphones in an ascending or descending order of pitch, it is heard as correspondingly ascending or descending in space. The illusion of spatial change that accompanies pitch change can be induced onto a pair of noise bursts by presenting them in synchrony with the tones. When cues known to produce stream segregation are introduced, the perceived position of the noises is less influenced by the tones. Stream organization is seen to be implicated in the ability to separately localize concurrent sources of sound. This suggests that "what" and "where" decisions are highly interactive and that neurological evidence that suggests separate pathways for these decisions must be interpreted with caution.In 1976, Deutsch and Roll reported an illusion obtained by playing a dichotic tonal sequence composed of three 800-Hz tones followed by two 400-Hz tones to one ear, and, in synchrony, three 400-Hz tones followed by two 800-Hz tones to the other ear. Many listeners heard only one sequence of tones that had the sequence of pitches received by the right ear (e.g., 400, 400, 400, 800, 8(0) but the sequence of positions occupied by the higher frequency, whatever its ear of arrival (e.g., L L L R R). This produced a percept in which, for example, the 400-Hz tone was heard at the left on the first event of the sequence, when in actual fact it had been presented to the right ear. Since the illusion seemed to represent a decoupling of the sources from which the listeners derived positional and pitch information, the authors suggested links between this effect and certain physiological findings that suggest there is a localizing system (the ventral route) and a nearly separate system (the dorsal route) involved in stimulus discrimination (Evans, 1974; Evans & Nelson, 1973a, 1973b. Is this why location and frequency information can be decoupled in the illusion mentioned earlier?One view of these systems might be that each one makes its own decision about the attribute with which it is concerned, and then decisions of the two systems are combined to represent sources of sound. DeutschWe acknowledge the assistance of Mimi Israel in data analysis, and the provision of a synthesizer by Richard Robinson and Lois Henderson. Some of the stimuli were made in the Computer

Low is large: spatial location and pitch interact in voice-based body size estimation

“…Our results build upon the classic Pratt effect (Pratt, 1930), demonstrating that pitch affects vertical elevation perception not only in a direct sound localization task (e.g., Bregman & Steiger, 1980;Morimoto & Aokata, 1984;Roffler & Butler, 1968;Trimble, 1934), but also in an indirect spatial task involving size estimation. Our findings suggest that the crossmodal correspondence between low pitch and largeness However, along the horizontal axis, there was a stronger association between rightward spatial cues and largeness for lowered-pitch than for raised-pitch voices when listeners were standing then when they were sitting.…”

“…Thus, we predicted that listeners would associate vertically high spatial cues with largeness for voices with raised pitch, but would associate vertically low spatial cues with largeness for those same voices with lowered pitch. This prediction was based largely on studies replicating the Pratt effect (Pratt, 1930), wherein auditory pitch cues override auditory spatial cues in a variety of sound localization tasks (see, e.g., Bregman & Steiger, 1980;Cabrera, Ferguson, Tilley, & Morimoto, 2005;Morimoto & Aokata, 1984;Roffler & Butler, 1968;Rusconi et al, 2006;Trimble, 1934). Although our task was not a direct task of sound localization, we predicted that a similar bias would characterize listeners' performance in an indirect vertical spatial task involving the estimation of size.…”

ARTSTREAM: a neural network model of auditory scene analysis and source segregation

“…If a tone located in the medial plane is captured by a left ear tone (due to frequency proximity), as opposed to a right ear tone, then the central tone will be perceived to come from the left side (Bregman and Steiger, 1980). The scale illusion of Deutsch (1975) also illustrates this point (Figure 7a).…”

“Octave illusion” or “Deutsch’s illusion”?

“…The main hypothesis of the present study aims at verifying some theoretical arguments which have been postulated in previous works (Bregman & Steiger, 1980;Chambers, Mattingley, & Moss 2002, 2004, according to which the most reliable explanation of the perceptual mechanism underlying the octave illusion is based on the primary harmonic relationship between the tones composing the dichotic pairs. However, surprisingly, little research has been carried out to test directly this explanation, and there is no scientiWc evidence describing whether the genesis of the illusion depends on the pitch interval between the tones composing the dichotic pairs.…”

“…Such an evidence could indicate whether the origin of the illusion depends on the frequency relationship between the tones composing the dichotic pairs. Indeed if the illusion occurs also with dichotic pairs composed of tones having frequency relationships diVerent from 2:1, the explanation of the illusion based on harmonic factors should be refused (Bregman & Steiger, 1980). To answer this question, in this study we presented alternated dichotic pairs arranged in sequences as described above, in which the interval between the two tones varies in extent in each sequence, from a minor third (frequency ratio, 6:5) to an eleventh (frequency ratio, 8:3), and asked the subjects to describe their percept.…”