Katie Carpenter

Intense interests are a defining feature of autism, yet their causal role in pragmatic language use remains poorly specified. We investigated whether intense interests directly shape conversational topic management, a core component of pragmatics, in two pre-registered experimental studies with 7–11-year-old children. Across both studies, we used a novel conversation elicitation paradigm that allowed experimental control within an otherwise naturalistic interaction. The experimenter embedded pre-planned conversational probes (e.g., “We like trips to castles”), and children’s responses were coded for appropriate topic acknowledgement and elaboration. During the Zoom-based conversation, children were also exposed to visual distractors via screenshare. Critically, these distractors—or the ongoing conversational topic—were manipulated to be either neutral or related to the child’s high-interest domain. In both studies, high-interest content systematically altered children’s topic management. In Study 1 (N = 132), children were less likely to maintain the conversational topic in the presence of high-interest distractors compared to neutral distractors. In Study 2 (N = 72), children were less likely to shift topic when a shift was pragmatically warranted (e.g., to comment on a warning sign) if the conversation involved a high-interest topic rather than a neutral one. Diagnostic status modulated these effects in different ways across studies. In Study 1, the disruptive effect of high-interest distractors was significantly greater for autistic children. In Study 2, there was no interaction between diagnostic status and interest condition. To move beyond categorical diagnostic comparisons, we conducted regression analyses treating interest intensity and autistic traits as continuous dimensions across all participants. In both studies, interest intensity explained substantial unique variance in topic management, with large effect sizes, even when controlling for autistic traits, cognitive flexibility, and core language abilities. These findings provide the first direct experimental evidence that intense interests exert a causal influence on conversational pragmatics. We argue that interest intensity is a key mechanistic variable for explaining individual differences in topic management across and within diagnostic groups and should be incorporated into theories of conversation and dialogue.

Conversational difficulties are an important part of the diagnostic criteria for autism. However, conversational behaviours amongst autistic children are highly variable. Some can be ‘conversationally reticent’, i.e. passive (or sometimes not responding at all). Another conversational behaviour seen in certain autistic individuals is verbosity. These conversational tendencies might reflect personality traits or the same individual might veer between verbosity and reticence depending on contextual factors, such as topic interest or difficulties managing routine change (Preference for Sameness). Both communication styles have social consequences but to date have received little attention. We investigated the following with parents of 109 six to twelve-year-olds with a confirmed autism diagnosis. Half attended special schools. 1. Do conversational styles in autistic children fall into two types, namely verbose versus reticent? 2. What other characteristics of autism influence these styles? Factor analysis found that a model in which verbosity and reticence are treated as distinct factors gave an excellent account of the data. We also found that greater ADHD traits were consistently related to higher levels of verbosity. Preference for Sameness was consistently found not to be a significant predictor in either. Greater speech and grammatical difficulties were consistently found to predict higher levels of reticence – but were not related to verbosity. For children’s interests, findings depended on the measure used. Interest Intensity was not a significant predictor but Preoccupations was a strong predictor of both verbosity and reticence. We discuss implications for supporting autistic children to achieve their social goals.