Selective attention to pitch amid conflicting auditory information: context-coding and filtering strategies

Abstract

An auditory Eriksen-flanker task was used to study how conflicting information interferes with selective attention to task-relevant differences in pure-tone frequency. Across the observation intervals of the discrimination task, the relevant frequency differences between target tones were positive, but within an observation interval, they could appear to be small or negative relative to conflicting differences in flanker tones leading or trailing the target. Being correct required attending to the between-target and ignoring the target-flanker pitch relation (across and within observation-interval, respectively). The interference index was an elevation of conflict-laden frequency discrimination thresholds (FDTs), relative to no-conflict FDTs. When conflicting differences in frequency or level (but not in duration) trailed the relevant differences, interference (i.e., FDT elevation) was large and persistent, increased with the target-flanker time proximity, but decreased with extensive training. Interference occurs when the target-flanker pitch relation is more prominent than the one between targets, and the physical and/or perceptual effects of relevant and conflicting differences tend to cancel one another, as with the above conflicting differences. With untrained participants, the target-flanker pitch relation is most prominent in conditions fostering both the perceptual grouping of the target and flanker (e.g., close time proximity), and the recency and salience of the conflicting differences (e.g., trailing conflicting difference); conversely, by lessening such grouping and salience, prolonged training decreases or nullifies the interference. The interference observed herein does not arise because the relevant and the conflicting differences each prompt separate decisions or responses that are in mutual conflict; instead, it arises from the early-stage interaction between their perceptual effects.

Auditory Conflict Resolution Correlates with Medial–Lateral Frontal Theta/Alpha Phase Synchrony

“…It is specifically activated when the subject is asked to pay attention selectively to one of two dichotically presented phonemes and ignore a simultaneously presented competing stimulus [34] . However, only a small number of auditory behavioral [35] , [36] and neuroimaging [32] , [34] studies on perceptual conflicts have been conducted in the auditory domain, especially at the early stage of object identification and selection, that is, the stimulus conflict. Here, we therefore tested the hypothesis that ACC may also support selective listening in complex auditory settings such as multitalker environments.…”

Aging-related attention deficits in frequency discrimination amid task-irrelevant stimulus differences

“…In frequency discrimination of tones lower than 2.0 kHz, an increase in level tends to cancel out the pitch shift induced by a positive frequency increment, but a decrease in level tends to enhance the pitch shift [13]; that is, the irrelevantlevel differences may lessen the perceptual effect of positive task-relevant frequency differences. In pitch-classification tasks [5], young adults perceive high-pitched, loud sounds as being more congruent than high-pitched, soft sounds; that is, pitch increments are perceived as been more similar to an increase than to a decrease in loudness.…”

“…In the irrelevant duration-difference (ÁT i ) condition, both comparisons included also positive 50-or 100-ms duration differences (ÁT i ). Figure 1 depicts the trial structure of the 3 conditions studied: control, ÁT i and ÁL i ; in terms of level or duration, both comparisons were different from S, but in terms of frequency only one comparison was different from S. To respond correctly, participants had to attend to ÁF r while attempting to ignore ÁL i or ÁT i [5,6]. In the 3I/2AFC task, the level or duration difference was only between the standard and the two comparisons, and the latter two were always equal in level or duration; participants could respond correctly by attending to the frequency difference between the two equallevel or equal-duration comparisons.…”

“…As a result, unveiling basic mechanisms accounting for failure to ignore IAI has remained elusive. To circumvent this limitation, in young and older adults, we are studying the ability to ignore IAI with psychoacoustic discrimination tasks and well-controlled stimuli [5,6]; here, we studied aging effects on the ability to ignore taskirrelevant level or duration differences while participants focused on task-relevant frequency differences. In order to engender task-irrelevant information in frequency-discrimination tasks the stimuli must include systematic (rather than random) and discernible differences along the task-relevant and a task-irrelevant dimension (e.g., level or duration).…”

“…Using the 3I/2AFC task, in a sample of young and one of older adults, we measured FDTs in the absence and in the presence of taskirrelevant level (ÁL i ) or duration (ÁT i ) differences. Since interactions between pitch and loudness are stronger than between pitch and duration [5,6], we predicted that ignoring ÁL i would be much harder than ÁT i , especially in older adults. Testing this prediction would determine if the older adult's attention deficit is all-inclusive entailing all combinations of task-relevant and task-irrelevant differences, or is specific entailing some combinations but not others; this test would unveil possible mechanisms accounting for failure to ignore irrelevant information.…”