Second-order relational properties and the inversion effect: testing a theory of face perception.

Recognition of faces is more severely impaired by inversion than is recognition of other types of objects. This was originally interpreted as evidence for the existence of special face-recognition mechanisms. Recently, Diamond and Carey (1986) attributed the inversion effect to the use of second-order relational properties that are important for, but not unique to, face recognition. According to their hypothesis, face recognition differs from the recognition of most other objects in its dependence on second-order relational properties. This hypothesis was tested in two experiments by comparing the effects of inversion on the identification of dot patterns that differed in the extent to which they required the encoding of second-order relational properties. Identification of the second-order relational patterns was not more disrupted by inversion than was identification of first-order patterns. These results fail to support the hypothesis that second-order relational properties are responsible for the inversion effect.