Tailored perception: Individuals' speech and music perception strategies fit their perceptual abilities.

Kyle Jasmin,Fred Dick,Lori L Holt,Adam Tierney

doi:10.1037/xge0000688

Abstract

Perception involves integration of multiple dimensions that often serve overlapping, redundant functions, for example, pitch, duration, and amplitude in speech. Individuals tend to prioritize these dimensions differently (stable, individualized perceptual strategies), but the reason for this has remained unclear. Here we show that perceptual strategies relate to perceptual abilities. In a speech cue weighting experiment (trial N = 990), we first demonstrate that individuals with a severe deficit for pitch perception (congenital amusics; N = 11) categorize linguistic stimuli similarly to controls (N = 11) when the main distinguishing cue is duration, which they perceive normally. In contrast, in a prosodic task where pitch cues are the main distinguishing factor, we show that amusics place less importance on pitch and instead rely more on duration cues—even when pitch differences in the stimuli are large enough for amusics to discern. In a second experiment testing musical and prosodic phrase interpretation (N = 16 amusics; 15 controls), we found that relying on duration allowed amusics to overcome their pitch deficits to perceive speech and music successfully. We conclude that auditory signals, because of their redundant nature, are robust to impairments for specific dimensions, and that optimal speech and music perception strategies depend not only on invariant acoustic dimensions (the physical signal), but on perceptual dimensions whose precision varies across individuals. Computational models of speech perception (indeed, all types of perception involving redundant cues e.g., vision and touch) should therefore aim to account for the precision of perceptual dimensions and characterize individuals as well as groups.

Highlights

Perception as categorizationPerception often involves integrating cues from multiple sources and arriving at a categorical interpretation
24 INDIVIDUALIZED PERCEPTION STRATEGIES In two categorization tasks, participants with amusia and control participants categorized stimuli varying across F0 and duration dimensions according to a phonetic distinction and a prosodic distinction
We found that when duration was the primary dimension, the amusic and control groups categorized each relying predominantly on duration (VOT) to signal category membership

Summary

Introduction

Perception as categorizationPerception often involves integrating cues from multiple sources and arriving at a categorical interpretation. Cues are integrated within a single sensory domain: when perceiving speech and music, individuals classify what they hear, mapping continuous spectral and temporal variation onto linguistic units, and tonal/rhythmic variation onto musical units. This process occurs at and among multiple putative levels simultaneously, as smaller units such as phonemes, syllables, and words are combined into larger structures such as phrases, clauses and sentences (Bentrovato, Devescovi, D'Amico, Wicha, & Bates, 2003; Elman, 2009; Lerdahl & Jackendoff, 1985; McMurray, Aslin, Tanenhaus, Spivey, & Subik, 2008; Utman, Blumstein, & Burton, 2000). It would seem that these difficulties have little effect on the overall success of speech perception: decades of research have consistently found that non-verbal auditory skills either do not correlate—or only weakly correlate—with speech perception ability in normal-hearing adults, and factor analyses consistently separate verbal and non-verbal sound perception into separate factors (Karlin, 1942; Kidd et al, 2007; Stankov & Horn, 1980; Surprenant & Watson, 2001; Watson & Kidd, 2002; Watson, Jensen, Foyle, Leek, & Goldgar, 1982)

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