FIAEs in Famous Faces are Mediated by Type of Processing

Abstract

An important question regarding face aftereffects is whether it is based on face-specific or lower-level mechanisms. One method for addressing this is to explore how adaptation in upright or inverted, photographic positive or negative faces transfers to test stimuli that are either upright or inverted and normal or negated. A series of studies are reported in which this is tested using a typical face identity aftereffect paradigm in unfamiliar and famous faces. Results showed that aftereffects were strongest when the adaptor matched the test stimuli. In addition, aftereffects did not transfer from upright adaptors to inverted test images, but did transfer from inverted adaptors to upright test images in famous faces. However, in unfamiliar faces, a different pattern was observed. The results are interpreted in terms of how identity adaptation interacts with low-level adaptation and highlight differences in the representation of famous and unfamiliar faces.

Keywords: adaptation; aftereffects; face processing; familiar faces; unfamiliar faces.

Figure 1

Examples of the stimuli used in this Experiment. (A) The unaltered 50% midpoint. (B) The inverted 50% midpoint. (C) The negated 50% midpoint. (D) The inverted and negated 50% midpoint.

Figure 2

The procedure for the experimentation. Those surrounded by the box are the adaptor repeated during the test phase.

Figure 3

Mean PSE (in identity strength needed to perceive the adapted identity) shift pre- to post-adaptation (as a measure of the magnitude of the aftereffect) for famous faces, when the adaptor is (A) upright and photographically positive, (B) upright and negated, (C) inverted and positive, and (D) inverted and negated. Darker bars represent upright test stimuli, lighter bars represent inverted test stimuli. Error bars represent standard error.

Figure 4

Mean PSE (in identity strength needed to perceive the adapted identity) shift pre- to post-adaptation (as a measure of the magnitude of the aftereffect) for unfamiliar faces, when the adaptor is (A) upright and photographically positive, (B) upright and negated, (C) inverted and positive, and (D) inverted and negated. Darker bars represent upright test stimuli, lighter bars represent inverted test stimuli. Error bars represent standard error.

Figure 5

Mean PSE (in identity strength needed to perceive the adapted identity) shift pre- to post-adaptation (as a measure of the magnitude of the aftereffect), for unaltered, low-pass, and high-pass filtered adaptation stimuli split by unaltered, low-pass, and high-pass filtered test stimuli for famous faces. Error bars represent standard error.

Figure 6

Mean PSE (in identity strength needed to perceive the adapted identity) shift pre- to post-adaptation (as a measure of the magnitude of the aftereffect), for unaltered, low-pass, and high-pass filtered adaptation stimuli split by unaltered, low-pass, and high-pass filtered test stimuli for unfamiliar faces. Error bars represent standard error.