Effects on face recognition of spatial-frequency information contained in inspection and test stimuli.

Researchers often assume a critical band of spatial frequencies is required for face recognition. Also, many studies have not measured the contrast required for recognition. On Day 1, observers viewed high-pass-filtered (HP), low-pass-filtered (LP), or unfiltered (UF) faces. On Day 2, they viewed a variety of faces, some of which were LP filtered, HP filtered, and UF. Observers adjusted contrast until they achieved both detection and recognition. Observers were most accurate and sensitive when filtered faces agreed in spatial-frequency content across days. Faces differing in spatial-frequency content were least well recognized. Unfiltered faces always fell between the 2 extremes. Observers generally used less contrast to recognize unfiltered than filtered faces. Correspondence of information between inspection and testing seemed more important than any particular range of frequencies.