Infants attend to second-order relational properties of faces.

Two experiments investigated whether 7-month-old infants attend to the spatial distance measurements relating internal features of the human face. A visual preference paradigm was used, in which two versions of the same female face (one either lengthened or shortened, and one nonmodified) were presented simultaneously. In Experiment 1, infants looked longer at the nonmodified faces, which were determined to match the average distance relationships found in a sample of faces drawn from the same population. Longer looking times for modified faces were found in Experiment 2, in which the nonmodified faces were unusually long and the modified faces conformed to average distance measurements. It is proposed that infants' attention to the spatial relations of internal face features is an optimal tool for lifelong face recognition.