Examining Pupillometric Measures of Cognitive Effort Associated with Speaker Variability During Spoken Word Recognition
Lillian R Douds · OhioLink ETD Center (Ohio Library and Information Network) · 2017
Speaker variability-idiosyncratic changes related to which speaker is talking, including voice, accent, and dialect-is an important aspect of everyday processing of speech.Human brains have the remarkable ability to process speech regardless of who is speaking, as long as the speech signal is clear and its phonetic properties are consistent with the listener's typical experience with the language spoken.Priming, the study of how an initial experience shapes responsiveness to a prior experience, has been used to study the effects of speaker variability on speech processing.Lee and Zhang (2016) provide evidence for greater priming when primes and targets are spoken by the same speaker compared to conditions in which the prime and target are spoken by different speakers.It may be that the priming associated with same-speaker conditions is related to a decrease in cognitive effort (the degree of mental energy required) to process primetarget pairs spoken by the same speaker as compared to different speakers.The current study examined the influence of speaker variability on cognitive effort, as indexed via pupillometry (measurement of pupil size).Results were analyzed according to each of three pupillometric dependent measures so that the relative merits of each measure for use in this context could be explored.For the same-speaker condition, there was a significant main effect of word relation according to peak dilation but not according to mean dilation and latency to peak dilation.Peak TERPs appear to be most sensitive for capturing cognitive effort associated with speaker variability via repetition priming.No significant main effect was observed in different-speaker conditions.Given that this was the first study to examine the role of cognitive effort associated with speaker variability during spoken word recognition, results provide a foundation for future research.