The influence of spatial separation on divided listening

Abstract

If spatial attention acts like a "spotlight," focusing on one location and excluding others, it may be advantageous to have all targets of interest within the same spatial region. This hypothesis was explored using a task where listeners reported keywords from two simultaneous talkers. In Experiment 1, the two talkers were placed symmetrically about the frontal midline with various angular separations. While there was a small performance improvement for moderate separations, the improvement decreased for larger separations. However, the dependency of the relative talker intensities on spatial configuration accounted for these effects. Experiment 2 tested whether spatial separation improved the intelligibility of each source, an effect that could counteract any degradation in performance as sources fell outside the spatial spotlight of attention. In this experiment, intelligibility of individual sources was equalized across configurations by adding masking noise. Under these conditions, the cost of divided listening (the drop in performance when reporting both messages compared to reporting just one) was smaller when the spatial separation was small. These results suggest that spatial separation enhances the intelligibility of individual sources in a competing pair but increases the cost associated with having to process both sources simultaneously, consistent with the attentional spotlight hypothesis.

Relative comparisons of call parameters enable auditory grouping in frogs

“…In humans, for example, grouping can occur over larger stimulus separations (180°) 9,23,32,33 than the minimum audible angle 34 . Indeed, the weakness of spatial or binaural cues in grouping is revealed by the fact that other cues can override them [35][36][37][38][39] . Likewise in frogs, assays of behavior, ear biomechanics, and neurophysiology show that auditory spatial resolution varies with source separations of 90° (ref.…”

Object-based auditory and visual attention

“…Listeners have difficulty making judgments of the relative timing of events across (but not within) streams [12]. When listeners are asked to divide attention between two speech streams that are close together in space, they are able to report many of the words in the two streams, but intermingle words from the two messages [44]. In contrast, when the two streams are spatially distinct, listeners are less likely to confuse words across streams, but also recall fewer words overall [44].…”

“…When listeners are asked to divide attention between two speech streams that are close together in space, they are able to report many of the words in the two streams, but intermingle words from the two messages [44]. In contrast, when the two streams are spatially distinct, listeners are less likely to confuse words across streams, but also recall fewer words overall [44]. These results hint that the more distinct competing streams are from one another, the more complete the suppression of the stream in the perceptual background.…”

“…3) Top-down attention and 4) streaming (across-time linkage based on bottom-up object continuity) help modulate the competition, biasing it to favor objects with desirable features and to maintain attention on the object already in the foreground [23,50]. 5) As a result, one object is emphasized at the expense of others in the scene [44]. Visual analogies of failed object formation.…”

Effects of Reverberant Spatial Cues on Attention-dependent Object Formation

“…Instead, local spectrotemporal cues such as harmonicity and common onsets generally determine how simultaneous sounds are grouped into objects. While spatial cues only weakly influence simultaneous grouping, they play a prominent role in sequential grouping and selective attention (Best et al 2006;Darwin 1997;Darwin and Hukin 1999;Freyman et al 1999;.…”