  Psychophysical experiments suggested a relative importance of a narrow band
of spatial frequencies for recognition of face identity in humans. There
exists, however, no conclusive evidence of why it is that such frequencies are
preferred. To address this question, I examined the amplitude spectra of a
large number of face images, and observed that face spectra generally fall off
steeper with spatial frequency compared to ordinary natural images. When
external face features (like hair) are suppressed, then whitening of the
corresponding mean amplitude spectra revealed higher response amplitudes at
those spatial frequencies which are deemed important for processing face
identity. The results presented here therefore provide support for that face
processing characteristics match corresponding stimulus properties.
