Listening to every other word: examining the strength of linkage variables in forming streams of speech.

In a variation on a procedure originally developed by Broadbent [(1952). "Failures of attention in selective listening," J. Exp. Psychol. 44, 428-433] listeners were presented with two sentences spoken in a sequential, interleaved-word format. Sentence one (target) comprised the odd-numbered words in the sequence and sentence two (masker) comprised the even-numbered words in the sequence. The task was to report the words in sentence one. The goal was to determine the effectiveness of cues linking the words of the target (or masker) over time. Three such "linkage variables" were examined: (1) fixed talker, (2) fixed perceived interaural location, and (3) correct syntactic structure. All of the linkage variables provided a significant advantage when applied to the target compared to the baseline condition in which the linkage variables were randomized. However, these linkage variables were not effective when applied to the masker. Word position effects were found such that performance in the baseline condition declined, and the advantages of the linkage variables increased, for the words near the end of the sentence. Overall, this approach appears to be useful for examining interference in speech recognition that has little or no peripheral component. The results suggest that variables that link target words together improve their resiliency to interference and/or their recall.