Own-gender bias in facial feature recognition yields sex differences in holistic face processing

Abstract

Introduction: Female observers in their luteal cycle phase exhibit a bias towards a detail-oriented rather than global visuospatial processing style that is well-documented across cognitive domains such as pattern recognition, navigation, and object location memory. Holistic face processing involves an integration of global patterns and local parts into a cohesive percept and might thus be susceptible to the influence of sex and cycle-related processing styles. This study aims to investigate potential sex differences in the part-whole effect as a measure a of holistic face processing and explores possible relationships with sex hormone levels.

Methods: 147 participants (74 male, 51 luteal, 22 non-luteal) performed a part-whole face recognition task while being controlled for cycle phase and sex hormone status. Eye tracking was used for fixation control and recording of fixation patterns.

Results: We found significant sex differences in the part-whole effect between male and luteal phase female participants. In particular, this sex difference was based on luteal phase participants exhibiting higher face part recognition accuracy than male participants. This advantage was exclusively observed for stimulus faces of women. Exploratory analyses further suggest a similar advantage of luteal compared to non-luteal participants, but no significant difference between non-luteal and male participants. Furthermore, testosterone emerged as a possible mediator for the observed sex differences.

Conclusion: Our results suggest a possible modulation of face encoding and/or recognition by sex and hormone status. Moreover, the established own-gender bias in face recognition, that is, female advantage in recognition of faces of the same gender might be based on more accurate representations of face-parts.

Fig. 1

A Experimental Setup: Participants were seated in front of a 24-inch computer screen at a viewing distance of ~ 57 cm. Participant’s heads were stabilized by a forehead and chin rest. Target faces were indicated with a right-handed right or left button press. B Trial Structure: Each trial started with 1000 ms central fixation, followed by 1000 ms target presentation (study phase), 500 ms scrambled face mask presentation and ended with side-by-side target and foil presentation until response (forced-response phase). Note, that the actual experiment used photorealistic face stimuli (see Sect. "Stimuli and procedure".), and the displayed images are for illustrative purposes only

Fig. 2

Sex differences in the part-whole effect. A Response accuracies: Female participants displayed a higher recognition accuracy in general. Male participants recognized significantly more whole faces compared to face parts, whereas no significant difference was present for female participants. B Reaction times: Male and female participants recognized face parts significantly faster compared to whole faces. This effect was significantly higher in male than in female participants. *p < 0.05, ** p < 0.01, ***p < 0.001. Notches represent the 95% CI for each median

Fig. 3

Effects of face gender on recognition accuracies in female and male participants for A face parts and B whole faces. While there was no difference in accuracies between faces of men and faces of women, female participants recognized significantly more face parts of women than face parts of men. Notches represent the 95% CI for each median

Fig. 4

Mediation of the relation between sex and part-whole effect through A progesterone, B estradiol and C testosterone. Dotted lines indicate indirect effects. Numbers in brackets represent controlled direct beta effects. Asterisks indicate statistically significant effects (p < 0.05). The effect of sex was partially mediated by testosterone, whereas no evidence for mediation by progesterone or estradiol emerged