Thatcher's children: development and the Thatcher illusion.

Children do not show the same recognition disadvantage for inverted faces as adults do. It has been suggested that this is because the configural encoding (which is disrupted by inversion) becomes more useful or available as we get older. The distinction between configural processing and featural processing, however, is not always clear--it may be a dichotomy or a continuum. The perceived normal-to-grotesque switch in the Thatcher illusion was investigated, as the image was rotated, by people aged between 6 and 75 years. No effect of age was found, with young children showing the same effects as adults--the switch occurring at about 72 degrees. The development of face processing and the nature of facial configural encoding are discussed in the light of this result.