ABSTRACT
To examine the effect of energetic and informational masking on the time-course of stream segregation, we presented listeners with semantically anomalous but syntactically correct target sentences (e.g., “A house should dash to the bowl”) that were masked by a two-talker speech masker or steady-state noise masker. To determine the effect of each masker on the time-course of stream segregation, we measured performance as a function of keyword position (key words in italics). The results from Experiment 1 showed that performance improved as a function of keyword position under speech masking, but was relatively stable across keyword positions under noise masking. The results of subsequent experiments showed that the variation in performance across keywords under speech masking was primarily due to the vocal similarities between the competing talkers, and that interference from the semantic content of the masker played a secondary role in undermining performance. Taken together, these results indicate that stream segregation takes longer to build up when a speech target is masked by other speech in the absence of cues that aid stream segregation (e.g., spatial separation), but that it 105takes little time to build up when a speech target is masked by a noise or when cues that aid stream segregation are available to listeners.
