Glimpsing speech in temporally and spectro-temporally modulated noise

Abstract

Speech recognition in fluctuating maskers is influenced by the spectro-temporal properties of the noise. Three experiments examined different temporal and spectro-temporal noise properties. Experiment 1 replicated previous work by highlighting maximum performance at a temporal gating rate of 4-8 Hz. Experiment 2 involved spectro-temporal glimpses. Performance was best with the largest glimpses, and performance with small glimpses approached that for continuous noise matched to the average level of the modulated noise. Better performance occurred with periodic than for random spectro-temporal glimpses. Finally, time and frequency for spectro-temporal glimpses were dissociated in experiment 3. Larger spectral glimpses were more beneficial than smaller, and minimum performance was observed at a gating rate of 4-8 Hz. The current results involving continuous speech in gated noise (slower and larger glimpses most advantageous) run counter to several results involving gated and/or filtered speech, where a larger number of smaller speech samples is often advantageous. This is because mechanisms of masking dominate, negating the advantages of better speech-information sampling. It is suggested that spectro-temporal glimpsing combines temporal glimpsing with additional processes of simultaneous masking and uncomodulation, and continuous speech in gated noise is a better model for real-world glimpsing than is gated and/or filtered speech.

Linguistic processing of task-irrelevant speech at a cocktail party

“…However, an important caveat precludes interpreting these findings as clear-cut evidence for semantic processing of task-irrelevant speech: Since these studies primarily involve presentation of arbitrary lists of words (mostly nouns), usually at a relatively slow rate, an alternative explanation is that the ISE is simply a result of occasional shifts of attention toward task-irrelevant stimuli ( Carlyon, 2004 ; Lachter et al, 2004 ). Similarly, the effects of informational masking discussed above can also be attributed to a similar notion of perceptual glimpsing, that is gleaning bits of the task-irrelevant speech in the short ‘gaps’ in the speech that is to-be-attended ( Cooke, 2006 ; Kidd et al, 2016 ; Fogerty et al, 2018 ). These claims – that effects of task-irrelevant speech are not due to parallel processing but reflect shifts of attention – are extremely difficult to reject empirically, as they would require insight into the listeners’ internal state of attention, which at present is not easy to operationalize.…”

“…Proponents of Late-Selection attention theories understand them as reflecting the system’s capability to apply linguistic processing to more than one speech stream in parallel, albeit mostly pre-consciously ( Deutsch and Deutsch, 1963 ; Parmentier, 2008 ; Parmentier et al, 2018 ; Vachon et al, 2020 ). However, others maintain an Early-Selection perspective, namely, that only one speech stream can be processed linguistically due to inherent processing bottlenecks, but that listeners may shift their attention between concurrent streams giving rise to occasional (conscious or pre-conscious) intrusions from task-irrelevant speech ( Cooke, 2006 ; Vestergaard et al, 2011 ; Fogerty et al, 2018 ). Adjudicating between these two explanations experimentally is difficult, due to the largely indirect-nature of the operationalizations used to assess linguistic processing of task-irrelevant speech.…”

Linguistic processing of task-irrelevant speech at a Cocktail Party

“…However, an important caveat precludes interpreting these findings as clear-cut evidence for semantic processing of task-irrelevant speech: Since these studies primarily involve presentation of arbitrary lists of words (mostly nouns), usually at a relatively slow rate, an alternative explanation is that the ISE is simply a result of occasional shifts of attention towards task-irrelevant stimuli (Carlyon 2004; Lachter et al 2004). Similarly, the effects of informational masking discussed above can also be attributed to a similar notion of perceptual glimpsing, i.e., gleaning bits of the task-irrelevant speech in the short ‘gaps’ in the speech that is to-be-attended (Cooke 2006; Kidd et al 2016; Fogerty et al 2018). These claims – that effects of task-irrelevant speech are not due to parallel processing but reflect shifts of attention – are extremely difficult to reject empirically, as they would require insight into the listeners’ internal state of attention, which at present is not easy to operationalize.…”

Capacity and tradeoffs in neural encoding of concurrent speech during Selective and Distributed Attention

“…Rather, it indicates that one speaker was tracked and encoded more accurately than the other , throughout the course of each trial. This preference could manifest either as dynamic shifts of attention between the two speakers, with overall more time spent attending to one vs. the other (‘glimpsing’; Vestergaard et al 2011; Fogerty et al 2018; Shavit-Cohen and Zion Golumbic 2019; Spadone et al 2021), or as a constant preference throughout the trial to one speaker (akin to Selective Attention). Indeed, several limiting factors preclude providing a more detailed account of how this biased listening strategy is employed from the current study.…”