Testing a two-component model of face identification: effects of inversion, contrast reversal, and direction of...

Enns and Shore (1997 Perception & Psychophysics 59 23-31) found additive effects of test orientation (upright or inverted) and direction of lighting (brow or chin lit) when they studied the inversion effect on face identification. A two-stage model was inferred in which inversion was processed by an orientation-sensitive component after which chin-lighting was processed by a lighting-sensitive component. Face identification is also strongly influenced by contrast reversal. A study is reported which aimed to (i) determine if contrast reversal interacts with lighting direction or orientation, findings that would support Enns and Shore's model; and (ii) to test their assumption that holistic encoding is prerequisite for their model by inducing featural encoding through training names to inverted faces. Names for unfamiliar brow-lit positive-contrast faces were trained with the faces upright or inverted. Identification accuracy was measured with combinations of orientation, lighting, and contrast. Consistent with their model, test orientation and direction of lighting were additive after training on upright faces and lighting and contrast reversal interacted. When holistic encoding was prevented following training on inverted faces, test orientation and lighting direction interacted for positive-contrast faces. Negative faces showed only an effect of direction of lighting. These results support Enns and Shore's two-stage model and their interpretation that orientation and direction of lighting interact following featural encoding of faces.