Informational masking: Counteracting the effects of stimulus uncertainty by decreasing target-masker similarity

Abstract

Previous work has indicated that target-masker similarity, as well as stimulus uncertainty, influences the amount of informational masking that occurs in detection, discrimination, and recognition tasks. In each of five experiments reported in this paper, the detection threshold for a tonal target in random multitone maskers presented simultaneously with the target tone was measured for two conditions using the same set of five listeners. In one condition, the target was constructed to be "similar" (S) to the masker; in the other condition, it was constructed to be "dissimilar" (D) to the masker. The specific masker varied across experiments, but was constant for the two conditions. Target-masker similarity varied in dimensions such as duration, perceived location, direction of frequency glide, and spectro-temporal coherence. Group-mean results show large decreases in the amount of masking for the D condition relative to the S condition. In addition, individual differences (a hallmark of informational masking) are found to be much greater in the S condition than in the D condition. Furthermore, listener vulnerability to informational masking is found to be consistent to at least a moderate degree across experiments.

Object-based auditory and visual attention

“…Many recent psychoacoustic studies link informational masking with stimulus similarity (i.e., similarity between target and maskers) and with stimulus uncertainty (e.g., randomness in the masker and/or target) [35,42]. While similarity and uncertainty affect informational masking, here I argue that they do so by affecting object formation and object selection.…”

“…The more unique and distinct the target features, the more effective top-down attention is in enhancing the target and suppressing any maskers [42]. Thus, object selection is a probabilistic competition that depends on interactions between bottom-up and top-down biases [43].…”

Issues in human auditory development

“…If that were the case, it would be difficult for an infant to tell when a tone has been added to a noise. In addition, variation in irrelevant sound has a distracting effect, even in adults (Durlach et al, 2003;Lutfi, Kistler, Oh, Wightman, & Callahan, 2003;Neff & Callaghan, 1988). Infants appear to demonstrate a similar effect when the experimenter varies the irrelevant sound, but if the infants' auditory system effectively varies a constant irrelevant sound, they may respond as if the sound itself had varied.…”

Does increasing the intelligibility of a competing sound source interfere more with speech comprehension in older adults than it does in younger adults?

“…Firstly, the competing speech is acoustically more similar to the target speech than is babble due to the prosodic and fine structure similarities, not to mention that the target and distracting lectures share the same voice. Considering that acoustic similarity is one of the most important determining factors for ease of stream segregation and level of informational masking (Agus, Akeroyd, Gatehouse, et al, 2009;Drullman & Bronkhorst, 2004;Durlach et al, 2003;Ezzatian, Li, Pichora-Fuller, & Schneider, 2012), we would expect the competing speech to produce more informational masking than 12-talker babble. Second, the semantic content in the competing speech is capable of activating the same semantic and linguistic process as the target speech; thus, it may interfere with comprehension of the target speech at more central levels (Boulenger et al, 2010;Rossi-Katz & Arehart, 2009).…”

“…This competing activation could make it more difficult to access the meaning of the words in the target speech. Because this interference is occurring after basilar membrane processing of the auditory input, it is classified as informational interference or informational masking (Durlach et al, 2003). In contrast, because a steady-state noise is unlikely to elicit any lexical activity, its effects on performance are considered to be primarily energetic.…”