Eye centring in portraits: a theoretical and empirical evaluation.

Tyler (1998 Nature 392 877) proposed that 'painters centre one eye in portraits', and that this is a hidden aesthetic principle used implicitly by artists and by viewers of portraits. We assess that hypothesis in three related studies: a Monte-Carlo analysis of eye placement in synthetic faces randomly placed within a frame; a survey of eye position in 786 painted portraits from Western art of the past six centuries; and an experimental study in which fifty subjects were asked which of two versions of 60 pairs of portraits they preferred, in only one of which the eye was precisely centred. Taken together, the three studies showed no evidence to support Tyler's hypothesis, and in particular there was no evidence for subjects having an aesthetic preference for a centred eye in portraits. We conclude that one eye tends to be relatively close to the vertical midline because of geometric constraints on the placing of a relatively large object, the head, within a pictorial frame.