Perceptual dimensions influence auditory category learning

Abstract

Human category learning appears to be supported by dual learning systems. Previous research indicates the engagement of distinct neural systems in learning categories that require selective attention to dimensions versus those that require integration across dimensions. This evidence has largely come from studies of learning across perceptually separable visual dimensions, but recent research has applied dual systems models to understanding auditory and speech categorization. Since differential engagement of the dual learning systems is closely related to selective attention to input dimensions, it may be important that acoustic dimensions are quite often perceptually integral and difficult to attend to selectively. We investigated this issue across artificial auditory categories defined by center frequency and modulation frequency acoustic dimensions. Learners demonstrated a bias to integrate across the dimensions, rather than to selectively attend and the bias specifically reflected a positive correlation between the dimensions. Further, we found that the acoustic dimensions did not equivalently contribute to categorization decisions. These results demonstrate the need to reconsider the assumption that the orthogonal input dimensions used in designing an experiment are indeed orthogonal in perceptual space as there are important implications for category learning.

Do Infants Really Learn Phonetic Categories?

“…After hearing nonspeech stimuli in which two auditory dimensions are perfectly correlated, listeners can discriminate between stimuli that follow the same correlation as in training, but not those that violate the correlation (Stilp et al, 2010 ; Stilp & Kluender, 2012 ), suggesting that correlations among dimensions can drive auditory perceptual space learning. The integration of perceptual dimensions for perceiving speech is not always determined by experience (Kingston et al, 2008 ; S. Lee & Katz, 2016 ), but several studies have suggested that an experience-based perceptual space learning process could play a role (Holt et al, 2001 ; Nearey, 1997 ; Schertz et al, 2020 ) and could interact in nontrivial ways with subsequent learning of cue weights (Roark et al, 2020 ; Roark & Holt, 2019 ; Scharinger et al, 2013 ).…”

Left-handed voices? Examining the perceptual learning of novel person characteristics from the voice

“…In auditory category learning studies, listeners are trained to be able to distinguish between two or more novel auditory categories. These studies report that listeners can in principle readily learn to recognise novel auditory categories, although overall accuracy of learning depends on the specific nature of the acoustic manipulation (e.g., Goudbeek et al, 2009;Scharinger et al, 2013;Roark & Holt, 2019;Holt & Lotto, 2008;Roark & Holt, 2018;Gabay et al, 2015).…”

“…Crucially, some of these studies have also directly explored how listeners use specific acoustic cues during learning to build representations of the newly-learned categories. In these studies, listeners are usually trained on recognise novel auditory categories that either differ in one acoustic property or two co-varying acoustic properties (Goudbeek et al, 2009, Scharinger et al, 2013Roark & Holt, 2019). When relating these acoustic properties to listeners' category judgements, during and after training these studies usually show that listeners at least partially base their category judgements on the acoustic properties that do indeed distinguish between the categories.…”

“…When relating these acoustic properties to listeners' category judgements, during and after training these studies usually show that listeners at least partially base their category judgements on the acoustic properties that do indeed distinguish between the categories. Depending on the nature of the relevant acoustic manipulation, however, listeners have at times been observed to apply non-optimal categorisation strategies: In these cases, listeners e.g., do not use one or more of the diagnostic acoustic properties to make category judgements or conversely base partially their judgements on acoustic properties that are in fact not diagnostic in differentiating categories (Goudbeek et al, 2009;Scharinger et al, 2013;Roark & Holt, 2019). The latter finding suggests that even in the presence of a perceptual blank slate -created by training people to recognise sound categories that have no direct real-world correspondence -perceptual preferences or biases exist.…”

“…The latter finding suggests that even in the presence of a perceptual blank slate -created by training people to recognise sound categories that have no direct real-world correspondence -perceptual preferences or biases exist. That is, listeners apply their prior experience with how sounds work in naturalistic settings to their learning of novel categories (Scharinger et al, 2013;Roark & Holt, 2019).…”