Performance on stochastic figure-ground perception varies with individual differences in speech-in-noise recognition and working memory capacity

Abstract

Speech recognition in noisy environments can be challenging and requires listeners to accurately segregate a target speaker from irrelevant background noise. Stochastic figure-ground (SFG) tasks in which temporally coherent inharmonic pure-tones must be identified from a background have been used to probe the non-linguistic auditory stream segregation processes important for speech-in-noise processing. However, little is known about the relationship between performance on SFG tasks and speech-in-noise tasks nor the individual differences that may modulate such relationships. In this study, 37 younger normal-hearing adults performed an SFG task with target figure chords consisting of four, six, eight, or ten temporally coherent tones amongst a background of randomly varying tones. Stimuli were designed to be spectrally and temporally flat. An increased number of temporally coherent tones resulted in higher accuracy and faster reaction times (RTs). For ten target tones, faster RTs were associated with better scores on the Quick Speech-in-Noise task. Individual differences in working memory capacity and self-reported musicianship further modulated these relationships. Overall, results demonstrate that the SFG task could serve as an assessment of auditory stream segregation accuracy and RT that is sensitive to individual differences in cognitive and auditory abilities, even among younger normal-hearing adults.

Temporal-Coherence Induces Binding of Responses to Sound Sequences in Ferret Auditory Cortex

“…For example, the proportional increase in STRF enhancements and rapid dynamics with the size of the figures ( Figs. 5 ) parallel well the higher detection accuracy and faster reaction times observed in humans [14] despite the absence of a behavioral task in our ferrets. The SFG stimulus mirrors many characteristics of signals in complex realistic settings, e.g., speech mixtures and orchestral musical streams.…”

“…As mentioned earlier, both experimental stimuli in Figures 1B & 1C have been explored in human psychoacoustic studies of stream segregation [1,9,14]. Our physiological responses are consistent with these behavioral findings in all aspects investigated.…”

“…Since coherent responses are hypothesized to bind the responsive cells ( Fig. 1B ), we expect to detect more enhanced responses with bigger Figures, which in turn leads to the perceptual “pop-out” of the Figure [14].…”

“…It is versatile in that it can readily be adjusted to different levels of difficulty by modifying the figure sizes, the jitter among its tones, or the density of the background tones. Thus, human subjects' perception of this stimulus has been shown to reflect their performance on the Quick Speech-in-Noise tasks as well as individual differences in working memory capacity and self-reported musicianship [14].…”

“…The fUS measurements in the older ferret K (supplementary Figure 6S) illustrate this point in that while the figure enhancements appeared robust, the dynamics of the process were noticeably slower. Aged human listeners have been shown to exhibit difficulties detecting low-rate stochastic FM modulations [34] as well as poorer speech comprehension in noise, much like the SFG subjects in [14]. If confirmed in more aged animals, this stimulus may well serve as a model for the mechanisms that cause the deterioration in the binding process [24][25][26].…”