Two-year-old children's sensitivity to the referential (in)efficacy of their own pointing gestures.

In three studies, two-year-old children communicated to a parent which of two out-of-reach objects contained a sticker. Across trials, the objects were positioned in different configurations so that it was possible or impossible for a child's pointing gesture to unambiguously specify one object. In Study 1, the objects used were two boxes distinguished by a different picture of a vehicle on the front, and children (n = 16; mean age 2;8) were significantly more likely to name the box's picture on trials where pointing alone could not unambiguously specify the box than on trials where it could. In Studies 2 and 3, the stickers were hidden inside different animal figures. Older two-year-olds (n = 16, mean age 2;9), but not younger two-year-olds (n = 16, mean age 2;4), showed an ability to recognize the referential (in)efficacy of their pointing gestures and to adapt their communication accordingly.