Does manipulating conversation partner speech rate impact autistic and neurotypical child response content and timing?

The ability to maintain a conversation topic is key to social relationships but is cognitively demanding. It requires rapid speech processing and simultaneous planning. Reduced speech rate might help children, particularly autistic children. Conversely, reduced speech rate is often socially dispreferred and thus might hinder reciprocal conversation. We test if and how speech rate affects responses which acknowledge and continue the topic (so-called ‘topic-supporting’ responses) and response timing. In a novel paradigm, children interact with a researcher whereby pre-recorded sentences (‘probes’) in the researcher’s voice are interspersed into naturalistic conversations. Probes are heard in two conditions: ‘Fast’ (80% of the original) or ‘Slow’ (140%). Of a target sample of 50 autistic and 50 neurotypical 6½ to 12 year-olds, we have tested 90 children to date. Following our pre-registered analysis plan, we will 1) run Diagnosis x Speech Rate mixed effects models for topic-supporting responses and timing 2) test if individual differences in autistic traits or language processing efficiency moderate any effects of speech rate. We discuss the advantages of combining experimental manipulation within semi-naturalistic conversation.