Think Fast! Mental-state Language is Related to the Speed of False-belief Reasoning in Adulthood

When tested appropriately, infants appear to demonstrate false-belief understanding in the first year of life. Some have argued that this is inconsistent with the well-established relationship between social experience and preschoolers’ false-belief performance. We argue that these two sets of findings are not inconsistent because the ability to attribute false beliefs to others is necessary but not sufficient for falsebelief performance, and we propose several ways that one social factor, hearing and using mental-state language, might relate to false-belief performance throughout the lifespan. We tested this account by examining the relationship between adults’ use of mental-state language and their false-belief understanding. Participants’ use of mental-state language was related to how quickly they could accurately predict the behavior of agents on the basis of desires and beliefs. These findings provide the first evidence that mental-state talk and false-belief performance are related into adulthood.