On the other-side of the mean: Perceiving the dissimilarity of faces

We created a “face space” using a laser scan representation of faces. In this space, a caricature can be made by moving a face away from the average, along the line connecting it to the average. If we go in the other direction, we can move the face through the mean and out the other side. We call the result of this process an “antiface” because it is an opposite, in a computational sense, to the original face. We morphed faces into their antifaces and sampled the transition in five discrete steps. We then collected similarity ratings for all possible pairs of morphed faces. The data revealed a perceptual discontinuity of face identity as the face crosses over to the other side of the mean. We consider these results in the context of face space models of human face processing