Perceptual versus cognitive speed in a time-compressed speech task

Abstract

Time-compression retains the information-bearing spectral change present uncompressed speech, although at a rate that may outstrip cognitive processing speed. To compare the relative importance of perceptual and cognitive processing speed, we compared the understanding of (1) time-compressed stimuli expanded in time via gaps with (2) uncompressed stimuli where spectral change information was removed. We hypothesized that, despite the initial compression, the compressed and expanded stimuli would be more intelligible as it would retain relatively more information-bearing spectral change. Participants were somewhat older listeners (mid-1950s to mid-1960s) with normal hearing or mild hearing loss. Stimuli were spoken seven-digit strings time-compressed via pitch synchronous overlap and add (PSOLA) at three uniform compression ratios (2:1, 3:1, and 5:1). In gap insertion conditions, the total duration of the compressed stimuli was restored via introduction of periodic gaps. This produced signal-to-gap ratios ...