Speech perception under adverse conditions: insights from behavioral, computational, and neuroscience research.

Sara Guediche,Sheila E Blumstein,Lori L Holt,Julie A Fiez

doi:10.3389/fnsys.2013.00126

Abstract

Adult speech perception reflects the long-term regularities of the native language, but it is also flexible such that it accommodates and adapts to adverse listening conditions and short-term deviations from native-language norms. The purpose of this article is to examine how the broader neuroscience literature can inform and advance research efforts in understanding the neural basis of flexibility and adaptive plasticity in speech perception. Specifically, we highlight the potential role of learning algorithms that rely on prediction error signals and discuss specific neural structures that are likely to contribute to such learning. To this end, we review behavioral studies, computational accounts, and neuroimaging findings related to adaptive plasticity in speech perception. Already, a few studies have alluded to a potential role of these mechanisms in adaptive plasticity in speech perception. Furthermore, we consider research topics in neuroscience that offer insight into how perception can be adaptively tuned to short-term deviations while balancing the need to maintain stability in the perception of learned long-term regularities. Consideration of the application and limitations of these algorithms in characterizing flexible speech perception under adverse conditions promises to inform theoretical models of speech.

Highlights

Hebb-TRACE (Mirman et al, 2006) is a modification of the interactive TRACE model (McClelland and Elman, 1986) that has an added Hebbian learning algorithm
NEUROIMAGING EVIDENCE FOR ADAPTIVE PLASTICITY IN SPEECH PERCEPTION In an attempt to dissociate neural changes directly related to adaptive plasticity from modulatory effects of factors such as predictive context and stimulus distortions, we review studies that have investigated changes in neural activity associated with adaptive plasticity (Adank and Devlin, 2010; Eisner et al, 2010; Kilian-Hutten et al, 2011a,b; Erb et al, 2013)
We have reviewed several parallel behavioral literatures that demonstrate that the perceptual system makes rapid adaptive adjustments in response to distorted acoustic speech input

Summary

SYSTEMS NEUROSCIENCE

The mapping of lower-level perceptual information to phonetic categories is adjusted via Hebbian learning such that subsequent perception of these consonants is more likely to activate the consonant consistent with the previous lexical context, even in the absence of the biasing context By this account, the same lexical feedback that influences online acoustic phonetic perception guides learning of the mapping of distorted speech onto pre-lexical representations. In the domain of adaptive plasticity for acoustic phonetic perception, Vroomen and colleagues suggested that “crossmodal conflict” is responsible for driving rapid changes in perception and noted the possibility that it provides a common mechanism for both lexically-mediated and visually-mediated adaptive plasticity (Vroomen et al, 2007; Vroomen and Baart, 2012) They argued that in both cases, a discrepancy (i.e., error signal) between the information provided by different sources of information (lexical, visual) and the information provided by the input sensory modality (ambiguous acoustic speech signal) leads to adaptive plasticity. Consideration of the mechanisms underlying prediction error signals, generally, and sensorimotor adaptation, may reveal a rapid and biologically-plausible neural mechanism for achieving adaptive plasticity in speech perception

INSIGHTS FROM COGNITIVE NEUROSCIENCE

Findings

CONCLUSIONS AND FUTURE DIRECTIONS