We examined visual attention allocation during a set of social videos that are intended to elicit the coordination of attention with another person, compared to a control condition. Deficits in joint attention are a characteristic of young children with autism spectrum disorder (ASD). Participants included a diverse sample of 50 typically developing school-aged children between 3 and 9 years of age (M = 6:3, SD = 1:8). Results demonstrated that gaze allocation differed significantly between the experimental and control condition. Further, individual differences in gaze allocation were significantly predicted by a parent-report measure evaluating features of the broad autism phenotype. This study contributes to a research program that aims to develop and validate an endophenotype measure of ASD.