Attributing false beliefs about object identity reveals a signature blind spot in humans' efficient mind-reading system.

How can human beings make significant but cognitively taxing inferences about others' beliefs yet also effectively "mind read" in fast-moving social situations? We tested the idea that humans have two mind-reading systems: a flexible system and an efficient system that can make fast calculations because it has natural blind spots to the kinds of input it processes. We showed that the automatic gaze anticipations of 3-year-olds, 4-year-olds, and adults displayed a signature blind spot specific to calculating an actor's false belief about object identity-a calculation that required the complex understanding that an object can be interpreted differently depending on one's visual perspective. Participants' deliberate verbal inferences demonstrated significant flexibility in calculations of another person's beliefs. Our results show that quick, efficient mind reading eschews conceptual sophistication.