Expressivity, but not age, is predictive of how 'readable' children's reactions are

Nonverbal behaviours are social tools, used to signal our intentions and feelings to our social partners. Successful communication should therefore depend upon our 'readability': how interpretable these nonverbal signals are. However, while children's ability to reliably interpret their social partners has been well researched, there is a lack of research into the development of readability. To address this gap, 36 typically developing 5- to 11-year-old children were covertly video recorded interacting with a researcher. This captured their naturalistic responses to four different social scenarios. Five-second, silent video clips of each child's reactions to each scenario were created and shown to 27 adult perceivers. These perceivers were then asked to infer which of the four potential scenarios each child was reacting to in each clip, allowing us to measure how 'readable' each child was. Perceivers were further asked to rate how expressive they felt each child was against a five-point Likert scale. This study was pre-registered on the OSF. This is the first study to demonstrate that children between 5 and 11-years-old are readable social actors. Contrary to our expectations, we found no significant effect of age on target readability. On the other hand, target's expressivity was significantly associated with their readability. These results have implications for our understanding of how children become successful communicators and suggest that readability might be a stable trait over this age range - varying between individuals in a similar manner to that previously observed in facial expressivity.