Speaker
Description
Speech comprehension relies on normalization mechanisms that help listeners cope with the natural variability in speech production. In speech rate normalization, for instance, the perception of an ambiguous target phoneme can be influenced by the rate of the preceding context. While previous research has demonstrated that both proximal and distal contexts contribute to the effect, they provide only limited insight into the the temporal structure of the rate integration window. This study uses a prosodic reverse correlation approach to assess how 100-millisecond segments within the context sentence contribute to the speech normalization effect. Eight pairs of ambiguous sentences were used, each participant categorizing one pair across 300 trials. On each trial, every segment was randomly time-compressed or stretched. Segment-based correlations between compression factors and responses reveal how speech rate across different segments influences perception. The results demonstrate a broad temporal integration window, with significant effects observed up to 1 second before the target. A detailed analysis of the correlation patterns across the eight sentences challenges the idea that loudness, lexical stress, or phonetic similarity alone drive speech rate integration. The presence of negative correlation coefficients further suggests that more complex mechanisms are involved in the temporal integration of speech rate.