Individual Differences in Speech Perception: Evidence from Visual Analogue Scaling and Eye-Tracking

This study investigated whether there were individual differences in within-category sensitivity to the voicing contrast and, if so, whether these differences were related to listeners‟ differential sensitivity to different acoustic cues. To do this, we conducted two speech perception experiments with English-speaking adults: visual analogue scaling (VAS) and anticipatory eye movement (AEM). Stimuli were a 30-item /ta/ to /da/ continuum, which systematically varied both VOT and f0. We found evidence of gradient sensitivity to within-category fine phonetic detail for both tasks. Consistent with previous research, we also found that listeners were more sensitive to changes in VOT than to changes in f0 for both tasks. Listeners who had a gradient response pattern on the VAS task showed evidence of sensitivity to f0 on the AEM task, while listeners who had a categorical response pattern on the VAS task did not. This result suggests that there are individual differences in responses to subphonemic detail and that these differences may be systematically related to sensitivity to different acoustic cues.