Self recognition of facial features in same-sex twins

Abstract

In order to distinguish recognition of an image of the self from identification of it, children were shown projected slides of faces of varying degrees of familiarity. Fifteen pairs of same sex twins with a mean age of 23 months were tested. After being habituated to multiple poses of the self, the twin, or another child of the same age and sex, children were shown a new pose of themselves, their twin and the other child. Duration of visual fixation, coy responses and smiling to these images were compared. Patterns of looking and smiling did not support the view that the image of the self was discriminated from that of the twin. The index of coy reaction, however, indicated that the two images may have been differentiated. Children displayed more coy responses to the novel image of themselves than to the image of their twin and the other child. Although the findings from all measures were not consistent, our results suggest that early in their second year children begin to distinguish their own facial features from the more familiar features of their twin. Coy behaviour is a more sensitive non-verbal index of this ability than either visual fixation or smiling.