Selective listening in checkerboard and interrupted speech stimuli with two talkers

Abstract

A two-talker situation is tougher than a single-talker situation when one has to selectively listen to a target speech. To simplify experimental conditions, we focused on the situation that two talkers speak different sentences alternating with each other. At the same time, we introduced two types of alternations: alternation only in time (staggered speech) and alternation in time and frequency (two-talker checkerboard speech). To our knowledge, the intelligibility of two-talker checkerboard speech stimuli had been never investigated. Three steps of segment duration (20, 80, and 320 ms) for both stimulus types and three steps of the number of frequency bands (4, 8, and 20) for checkerboard speech stimuli were employed. Japanese native listeners (N = 10 or 22; age range: 21–34) successfully heard out a specific talker’s sentence while ignoring the other for both stimulus types. The intelligibility curves of two-talker checkerboard speech stimuli exhibited characteristic U-shaped curves as found in the previous investigations with one-talker checkerboard speech stimuli (although the intelligibility for two-talker checkerboard speech stimuli went down by 5–20%), suggesting that a common auditory grouping mechanism works in this case also.