A Picture Is Worth a Thousand Words: Reply to "On the Difficulty of Averaging Faces"
Pittenger (PS, 1991, 2, 351-353) criticizes three characteristics of our technique of mathematically averaging faces to produce an attractive composite face (Langlois & Roggman, 1990). He claims that our procedure compromises the "... ability to recover either morphologically normal faces or mental prototypes of faces" and compromises "the ability to recover optimum structure" of faces. The problems he cites are: (1) averaging the gray values of a matrix of the whole face rather than averaging spatial locations of anatomically defined features; (2) using two-dimensional rather than three-dimensional representations of faces; and (3) using a "mean" as a measure of central tendency rather than using a true "optimum value" or some other measure of central tendency.
A Picture Is Worth a Thousand Words: Reply to "On the Difficulty of Averaging Faces" Judith H. Langlois, Lori A. Roggman, Lisa Musselman and Scott Acton Psychological Science Vol. 2, No. 5 (Sep., 1991) (pp. 354-357)