Selectivity of face distortion aftereffects for differences in expression or gender

Abstract

The perceived configuration of a face can be strongly biased by prior adaptation to a face with a distorted configuration. These aftereffects have been found to be weaker when the adapt and test faces differ along a number of dimensions. We asked whether the adaptation shows more transfer between faces that share a common identity, by comparing the strength of aftereffects when the adapt and test faces differed either in expression (a configural change in the same face identity) or gender (a configural change between identities). Observers adapted to expanded or contracted images of either male or female faces with either happy or fearful expressions, and then judged the perceived configuration in either the same faces or faces with a different gender and/or expression. The adaptation included exposure to a single face (e.g., expanded happy) or to alternated faces where the distortion was contingent on the attribute (e.g., expanded happy versus contracted fearful). In all cases the aftereffects showed strong transfer and thus only weak selectivity. However, selectivity was equal or stronger for the change in expression than gender. Our results thus suggest that the distortion aftereffects between faces can be weakly modulated by both variant and invariant attributes of the face.

Keywords: adaptation; aftereffects; face perception; facial expressions.

Figure 1

Test faces corresponding to a happy female, happy male, fearful female, or fearful male. For each the face was distorted from maximally contracted (0) to maximally expanded (100). The original, undistorted face is shown in the middle column, corresponding to a level of 50.

Figure 2

Aftereffects for adapt and test faces with the same expression and gender. The aftereffects are plotted as the difference in the perceived neutral point for each test face after adapting to an expanded face versus a contracted face. The faces corresponded to the male and female models with a happy, fearful, or neutral expression. Panels plot the settings for the two individual observers and the average.

Figure 3

Adaptation to a single image. After adapting to a single face image, the observers were presented with one of four test face images, which included the same adapt face, a face differing in expression, a face differing in gender, and a face differing in both expression and gender.

Figure 4

Transfer of adaptation across individual faces. Aftereffects are plotted as the difference between the settings following adaptation to expanded or contracted faces. Sets of bars correspond to the four adapt faces (hm, happy male; fm, fearful male; hf, happy female; and ff, fearful female) or to the average for the four adapting faces. For each the bars show the settings when the test face was the same as the adapt (black), differed in expression (dark gray), gender (light gray), or both attributes (unfilled). Each panel plots the settings for the five individual observers or the average.

Figure 5

Contingent adaptation. Observers adapted to an alternation between two faces with opposite distortions that differed in either gender or expression, and then judged the apparent distortion in each gender or expression.

Figure 6

Aftereffects for the contingent adaptation for expression or gender. Bars plot the difference between the settings for the happy or fearful face (left) or male or female face (right) after adapting to opposing distortions in the faces. Panels show the settings for the four observers or the mean.

Figure 7

Face sets shown for adaptation to populations of female or male, or happy or fearful faces.

Figure 8

Adaptation to different face sets with different attributes. Observers viewed an alternation between two faces with opposite distortions that were drawn at random from sets that differed in either gender and/or expression, and then judged the apparent distortion in each gender and/or expression.

Figure 9

Adaptation to opposing distortions in sets of faces. Bars plot the settings for the two opposing conditions when the sets of faces differed in expression, gender, both gender and expression, or conjunctions of gender and expression. Panels show the settings for four observers or the mean.