Accounting for rate-dependent category boundary shifts in speech perception
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- 作者：Hans Rutger Bosker
- 关键词：Speech rate ; Rate ; dependent perception ; Rate normalization ; Durational contrast ; Neural entrainment
- 刊名：Attention, Perception, & Psychophysics
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：79
- 期：1
- 页码：333-343
- 全文大小：829KB
- 刊物主题：Cognitive Psychology;
- 出版者：Springer US
- ISSN：1943-393X
- 卷排序：79
文摘
The perception of temporal contrasts in speech is known to be influenced by the speech rate in the surrounding context. This rate-dependent perception is suggested to involve general auditory processes because it is also elicited by nonspeech contexts, such as pure tone sequences. Two general auditory mechanisms have been proposed to underlie rate-dependent perception: durational contrast and neural entrainment. This study compares the predictions of these two accounts of rate-dependent speech perception by means of four experiments, in which participants heard tone sequences followed by Dutch target words ambiguous between /ɑs/ “ash” and /a:s/ “bait”. Tone sequences varied in the duration of tones (short vs. long) and in the presentation rate of the tones (fast vs. slow). Results show that the duration of preceding tones did not influence target perception in any of the experiments, thus challenging durational contrast as explanatory mechanism behind rate-dependent perception. Instead, the presentation rate consistently elicited a category boundary shift, with faster presentation rates inducing more /a:s/ responses, but only if the tone sequence was isochronous. Therefore, this study proposes an alternative, neurobiologically plausible account of rate-dependent perception involving neural entrainment of endogenous oscillations to the rate of a rhythmic stimulus.