Study title

The datasets comprise behavioural responses to speech stimuli. These stimuli are either simplified analogues of spoken sentence-length utterances or syllables (for datasets 1-4 and 6) or signal-processed natural syllables (for dataset 5). For the utterances, the responses are the transcriptions entered by the participant using a keyboard. For the syllables, the responses are key presses indicating the perceived identity of the initial consonant. Much of the information necessary to understand speech (acoustic-phonetic information) is carried by the changes in frequency over time of a few broad peaks in the frequency spectrum of the speech signal, known as formants. The project aims to investigate how listeners presented with mixtures of target speech and interfering formants are able to group together the appropriate formants, and to reject others, such that the speech of the talker we want to listen to can be understood. Interfering sounds can have two kinds of effect - energetic masking, in which the neural response of the ear to the target is swamped by the response to the masker, and informational masking, in which the "auditory brain" fails to separate readily detectable parts of the target from the masker. The project will explore the informational masking component of interference - often the primary factor limiting speech intelligibility - using stimulus configurations that eliminate energetic masking. The project will explore how speech-like interferers affects intelligibility, distinguishing the circumstances in which the interferer takes up some of the available perceptual processing capacity from those in which specific properties of the interferer intrude into the perception of the target speech. Our approach is to use artificial speech-like stimuli with precisely controlled properties, to accompany target speech with carefully designed interferers that offer alternative grouping possibilities, and to measure how manipulating the properties of these...