This study examines the temporal and directional characteristics of child-adult vocal exchanges in day-long naturalistic recordings of autism and typical control groups. In both populations, adults responded frequently (on average about 40% of responses) within 1s or less, a time thought to be conducive for contingency learning by the child. However, the time to adult response tended to be longer for the autism population. In the autism group, children also tended to follow more and lead less relative to the control group, as measured by differences in diagonal recurrence profiles computed based on cross recurrence plots. The results inform on the dynamics of naturalistic communicative interaction in normal development and therefore on the social context in which language develops. They also illustrate how large datasets and modern interaction analyses can expand our understanding of differences in children with autism, a population with both social and language deficits.