Young children's use of a delayed video representation to solve a retrieval problem pertaining to self.

The experiments reported here were concerned with the development of delayed self-recognition. Children were videotaped playing a game and were marked covertly with a sticker on their forehead while doing so. The findings, of both a cross-sectional sample and a prospective longitudinal one, revealed that 3- but not 2.5-year-old children reached to remove this sticker reliably during video playback only after they had been trained to use the video to guide their search for an object that was not directly visible to the unaided eye. It appears that by 3 years of age children understand that their briefly delayed self video-representation is related to their present self. In contrast, while 2.5-year-olds can use delayed video information to locate objects in space that cannot be seen by the unaided eye, they cannot use this type of information to locate an object that pertains to a part of self that is not directly visible, such as a sticker on one's hair. The findings are discussed in terms of the emergence of an extended sense of self.