Matching person identity from facial line drawings.

The processing of facial line drawings was investigated in either simultaneous or sequential matching trials with either the same or different viewpoint, showing pictures of faces either in the same modes (both photographs or line drawings) or different modes (one in each mode). Line drawings were particularly difficult to match in memory rather than under perceptual conditions, and line drawings did not allow the creation of efficient structural codes. These deficits of line representations underline the assumption that the face-processing system is inflexible when it is confronted with edge-based material.