Recognising the usual orientation of one's own face: the role of asymmetrically located details.

Our ability to recognise the usual horizontal orientation of our own face (mirror orientation) as compared with another very familiar face (normal orientation) was examined in experiment 1. Participants did not use the same kind of information in determining the orientation of their own face as in determining the orientation of the other familiar face. The proportion of participants who reported having based their judgment on the location of an asymmetric feature (eg a mole) was higher when determining the orientation of their own face than when determining that of the other familiar face. In experiment 2, participants were presented with pairs of manipulated images of their own face and of another familiar face showing conflicting asymmetric features and configural information. Each pair consisted of one picture showing asymmetric features of a given face in a mirror-reversed position, while the facial configuration was left unchanged; and one picture in which the location of the asymmetric features was left unchanged, while the facial configuration was mirror-reversed. As expected from the hypothesis that asymmetric local features are more frequently used for the judgment of one's own face, participants chose the picture showing mirror-reversed asymmetric features when determining the usual orientation of their own face significantly more often than they chose the picture showing normally oriented asymmetric features when determining the orientation of the other face. These results are explained in terms of competing forward and mirror-reversed representations of one's own face.