Why faces are and are not special: an effect of expertise.

TLDR: For instance, the authors showed that for dog experts sufficiently knowledgeable to identify dogs of the same breed, memory for photographs of dogs of that breed is as disrupted by inversion as is face recognition.

Abstract: Recognition memory for faces is hampered much more by inverted presentation than is memory for any other material so far examined. The present study demonstrates that faces are not unique with regard to this vulnerability to inversion. The experiments also attempt to isolate the source of the inversion effect. In one experiment, use of stimuli (landscapes) in which spatial relations among elements are potentially important distinguishing features is shown not to guarantee a large inversion effect. Two additional experiments show that for dog experts sufficiently knowledgeable to individuate dogs of the same breed, memory for photographs of dogs of that breed is as disrupted by inversion as is face recognition. A final experiment indicates that the effect of orientation on memory for faces does not depend on inability to identify single features of these stimuli upside down. These experiments are consistent with the view that experts represent items in memory in terms of distinguishing features of a different kind than do novices. Speculations as to the type of feature used and neuropsychological and developmental implications of this accomplishment are offered. Perception of human faces is strongly influenced by their orientation. Although inverted photographs of faces remain identifiable, they lose expressive characteristics and become difficult or impossible to categorize in terms of age, mood, and attractiveness. Failure to recognize familiar individuals in photographs viewed upside down is a well-known phenomenon (see, e.g., Arnheim, 1954; Attneave, 1967; Brooks & Goldstein, 1963; Kohler, 1940; Rock, 1974; Yarmey, 1971). Rock argued that because the important distinguishing features of faces are represented in memory with respect to the normal upright, an inverted face must be mentally righted before it can be recognized. He showed that it is difficult to reorient stimuli that have multiple parts, and especially difficult to recognize inverted stimuli in which distinguishing features involve relations among adjacent contours. Faces appear rich in just this sort of distinguishing feature; on these grounds they might be expected to be especially vulnerable to inversion. Thompson's (1980) "Thatcher illusion" provides a striking demonstration that spatial relations among features crucial in the perception of upright faces are not apparent when faces are upside down. In standard recognition memory paradigms, faces presented for inspection upside down and later presented for recognition (still upside down) are much more poorly discriminated from distractors than if the photographs are inspected and then rec