Abstract
The presence of non-simultaneous maskers can result in strong impairment in auditory intensity resolution relative to a condition without maskers, and causes a complex pattern of effects that is difficult to explain on the basis of peripheral processing. We suggest that the failure of selective attention to the target tones is a useful framework for understanding these effects. Two experiments tested the hypothesis that the sequential grouping of the targets and the maskers into separate auditory objects facilitates selective attention and therefore reduces the masker-induced impairment in intensity resolution. In Experiment 1, a condition favoring the processing of the maskers and the targets as two separate auditory objects due to grouping by temporal proximity was contrasted with the usual forward masking setting where the masker and the target presented within each observation interval of the two-interval task can be expected to be grouped together. As expected, the former condition resulted in a significantly smaller masker-induced elevation of the intensity difference limens (DLs). In Experiment 2, embedding the targets in an isochronous sequence of maskers led to a significantly smaller DL-elevation than control conditions not favoring the perception of the maskers as a separate auditory stream. The observed effects of grouping are compatible with the assumption that a precise representation of target intensity is available at the decision stage, but that this information is used only in a suboptimal fashion due to limitations of selective attention. The data can be explained within a framework of object-based attention. The results impose constraints on physiological models of intensity discrimination. We discuss candidate structures for physiological correlates of the psychophysical data.
Highlights
The intensity of an auditory stimulus is one of the most important basic attributes of auditory perception, besides pitch and spatial localization
The aim of this study was to test the hypothesis that the strong impairment in intensity resolution caused by non-simultaneous maskers can, at least in part, be attributed to the failure to selectively attend to the target tones and to ignore the maskers
Before introducing the two experiments, we provide a brief description of effects of non-simultaneous masking on intensity resolution, and of models proposed for these effects
Summary
The intensity of an auditory stimulus is one of the most important basic attributes of auditory perception, besides pitch and spatial localization. The aim of this study was to test the hypothesis that the strong impairment in intensity resolution caused by non-simultaneous maskers can, at least in part, be attributed to the failure to selectively attend to the target tones and to ignore the maskers. To this end, we compared intensity resolution under non-simultaneous masking in two types of conditions. Returning to the less complex stimulus configuration used in an intensity discrimination task with non-simultaneous maskers, we tested the hypothesis that the perceptual grouping of the target and the masker(s) into separate objects (cf [12,13]) facilitates selective attention to the target and reduces the masker-induced impairment in intensity discrimination. Many subjects in our previous experiments on forwardmasked intensity discrimination [10,26,27,28] reported to hear the target tone presented shortly after an intense masker as a weak ‘‘echo’’, which would be a clear example of perceiving the two tones as one unitary object
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
