This is just wild speculation. You overestimate the external validity of this study. Why did adults leap faster to conclusions? One obvious explanation would be

This is just wild speculation. You overestimate the external validity of this study. Why did adults leap faster to conclusions? One obvious explanation would be that adults are simply smarter and can get to a working heuristic faster. Maybe, maybe not, but we can’t know because the incentives in the study were ill-defined.