Cognitive Load Reduces Perceived Linguistic Convergence Between Dyads.

Speech convergence is the tendency of talkers to become more similar to someone they are listening or talking to, whether that person is a conversational partner or merely a voice heard repeating words. To elucidate the nature of the mechanisms underlying convergence, this study uses different levels of task difficulty on speech convergence within dyads collaborating on a task. Dyad members had to build identical LEGO® constructions without being able to see each other's construction, and with each member having half of the instructions required to complete the construction. Three levels of task difficulty were created, with five dyads at each level (30 participants total). Task difficulty was also measured using completion time and error rate. Listeners who heard pairs of utterances from each dyad judged convergence to be occurring in the Easy condition and to a lesser extent in the Medium condition, but not in the Hard condition. Amplitude envelope acoustic similarity analyses of the same utterance pairs showed that convergence occurred in dyads with shorter completion times and lower error rates. Together, these results suggest that while speech convergence is a highly variable behavior, it may occur more in contexts of low cognitive load. The relevance of these results for the current automatic and socially-driven models of convergence is discussed.