Influence of Task-Relevant and Task-Irrelevant Feature Continuity on Selective Auditory Attention

Abstract

Past studies have explored the relative strengths of auditory features in a selective attention task by pitting features against one another and asking listeners to report the words perceived in a given sentence. While these studies show that the continuity of competing features affects streaming, they did not address whether the influence of specific features is modulated by volitionally directed attention. Here, we explored whether the continuity of a task-irrelevant feature affects the ability to selectively report one of two competing speech streams when attention is specifically directed to a different feature. Sequences of simultaneous pairs of spoken digits were presented in which exactly one digit of each pair matched a primer phrase in pitch and exactly one digit of each pair matched the primer location. Within a trial, location and pitch were randomly paired; they either were consistent with each other from digit to digit or were switched (e.g., the sequence from the primer's location changed pitch across digits). In otherwise identical blocks, listeners were instructed to report digits matching the primer either in location or in pitch. Listeners were told to ignore the irrelevant feature, if possible, in order to perform well. Listener responses depended on task instructions, proving that top-down attention alters how a subject performs the task. Performance improved when the separation of the target and masker in the task-relevant feature increased. Importantly, the values of the task-irrelevant feature also influenced performance in some cases. Specifically, when instructed to attend location, listeners performed worse as the separation between target and masker pitch increased, especially when the spatial separation between digits was small. These results indicate that task-relevant and task-irrelevant features are perceptually bound together: continuity of taskirrelevant features influences selective attention in an automatic, obligatory manner, consistent with the idea that auditory attention operates on objects.

Perceiving sequential dependencies in auditory streams

“…Their results suggested that relevant and irrelevant features tend to be bound together and, the greater the separation between sequential elements along the taskirrelevant dimension, especially pitch, the more interference it produced. Despite the differences in stimuli and task, our results appear to be broadly consistent with those of Maddox and Shinn-Cunningham (2012). Although the detrimental effect we found here was significant, it was surprisingly small.…”

The role of syntax in maintaining the integrity of streams of speech

“…The conclusion about the efficacy of voice and location cues from the current study is based on the findings indicating that speech identification performance was much above chance when such cues were the only basis for selecting the target words (e.g., by randomizing the complementary variable in the non-syntactic word order conditions; cf. Best et al, 2008;Maddox and Shinn-Cunningham, 2012). The finding that there was a significant difference in performance observed between the two a priori cues under speech masking conditions, as indicated by the pooled analysis reported in the preceding section, suggests that they differed in the degree to which they aided speech stream selection.…”

T'ain't the way you say it, it's what you say – Perceptual continuity of voice and top–down restoration of speech

“…These give information about the size and the sex of a speaker (Hillenbrand and Clark, 2009;Smith et al, 2007;Titze, 1989), and can also play an important role for the intelligibility of speech in adverse listening scenarios (Darwin et al, 2003;. Furthermore, continuity of these vocal characteristics influences speech recognition performance Kidd et al, 2008;Maddox and Shinn-Cunningham, 2012;Shinn-Cunningham et al, 2013), suggesting that F0 and VTL are used to perceptually construct a speech stream (Gaudrain et al, 2007;Tsuzaki et al, 2007) by linking successive segments of speech over time. Hence, grouping successive segments of speech with different vocal characteristics should be more difficult in comparison with grouping speech segments from the same voice, and if the grouping rule of the continuity percept is a prerequisite for the repair mechanisms of missing speech segments, the voice manipulations that cause a disruption at the indexical level should reduce phonemic restoration benefit.…”