Male or Female? - Influence of Gender Role and Sexual Attraction on Sex Categorization of Faces

The categorization of dominant facial features, such as sex, is a highly relevant function for social interaction. It has been found that attributes of the perceiver, such as their biological sex, influence the perception of sexually dimorphic facial features with women showing higher recognition performance for female faces than men. However, evidence on how aspects closely related to biological sex influence face sex categorization are scarce. Using a previously validated set of sex-morphed facial images (morphed from male to female and vice versa), we aimed to investigate the influence of the participant’s gender role identification and sexual orientation on face sex categorization, besides their biological sex. Image ratings, questionnaire data on gender role identification and sexual orientation were collected from 67 adults (34 females). Contrary to previous literature, biological sex per se was not significantly associated with image ratings. However, an influence of participant sexual attraction and gender role identity became apparent: participants identifying with male gender attributes and showing attraction toward females perceived masculinized female faces as more male and femininized male faces as more female when compared to participants identifying with female gender attributes and attraction toward males. Considering that we found these effects in a predominantly cisgender and heterosexual sample, investigation of face sex perception in individuals identifying with a gender different from their assigned sex (i.e., transgender people) might provide further insights into how assigned sex and gender identity are related.

Sex Categorization from Faces: Other-race and other-species effect

Humans are very good at perceiving the sex of others by just glancing at their faces, but, it is still not well understood whether this ability can be generalized to faces from other-races or to non-humans. Therefore, the main purpose of this study is to test whether human adults could expand their sex categorization ability to faces that belongs to other-race and other-species. In order to examine this, 46 Caucasian participants were given a sex categorization task consisting of Caucasian (own-race), Asian (other-race) and chimpanzee (other-species) faces. Results showed that Caucasian faces were categorized significantly more accurately and quickly than Asian faces, and Asian faces categorized more accurately and quickly than chimpanzee faces, suggesting a strong other-race and other-species effect. Furthermore, consistent with previous literature, male faces were categorized more accurately and quickly compared to female faces. Moreover, facial metric analysis revealed that observers utilized eye height, brow to eye distance, and nose width distances during the sex categorization task for all three categories. Our results provide further evidence that similar facial metric cues were used to categorize the sex of other-race and other-species faces.

Centering Transgender Individuals in Forensic Anthropology and Expanding Binary Sex Estimation in Casework and Research

Due to disproportionate violence impacting the transgender community, forensic anthropologists may encounter the remains of trans individuals; however, it is unknown how often trans individuals are represented in casework and if practitioners have sufficient knowledge about trans bodies. After contextualizing forensically relevant demographics for the trans community, this study uses survey data of forensic anthropologists to critically explore the collective knowledge of and experience working with trans individuals; practitioners’ perceptions of sex and gender; and potential opportunities for trans-oriented research. The results indicate that 28.9% of respondents have worked with trans individuals in casework, but most forensic anthropologists were unfamiliar with forms and evidence of gender affirming procedures. Additionally, the survey indicates that forensic anthropologists struggle with the binary nature of forensic sex estimation, with 42.4% agreeing that sex is binary and 56.2% disagreeing. Similar opposition was found with reporting gender: 39.5% indicated that gender should be reported in casework and 31.0% disagreed. Moreover, current sex estimation methods are: rigidly binary; not reflective of human biological variation; and inadequate for trans individuals as they are based on assigned sex. To dismantle rigidly binary sex categorization, we propose the adoption of a biocultural and queer theoretical approach to forensic sex estimation and in sexual dimorphism research that challenges heteronormative assumptions, questions typological two-sex categorization, and combats the presumptions that gender and sex are stable, independent entities that convey universal meaning. Relatedly, the expansion of trans-oriented research, which is supported by 95.8% of respondents, will further improve methodological accuracies.

The Other-Race and Other-Species Effect during a Sex Categorization Task: An Eye Tracker Study

Sex categorization from faces is a crucial ability for humans and non-human primates for various social and cognitive processes. In the current study, we performed two eye tracking experiments to examine the gaze behavior of participants during a sex categorization task in which participants categorize face pictures from their own-race (Caucasian), other-race (Asian) and other-species (chimpanzee). In experiment 1, we presented the faces in an upright position to 16 participants, and found a strong other-race and other-species effect. In experiment 2, the same faces were shown to 24 naïve participants in an upside-down (inverted) position, which showed that, although the other-species effect was intact, other-race effect disappeared. Moreover, eye-tracking analysis revealed that in the upright position, the eye region was the first and most widely viewed area for all face categories. However, during upside-down viewing, participants’ attention directed more towards the eye region of the own-race and own-species faces, whereas the nose received more attention in other-race and other-species faces. Overall results suggest that other-race faces were processed less holistically compared to own-race faces and this could affect both participants’ behavioral performance and gaze behavior during sex categorization. Finally, gaze data suggests that the gaze of participants shifts from the eye to the nose region with decreased racial and species-based familiarity.

Sex Categorization of Faces: The Effects of Age and Experience

The face own-age bias effect refers to the better ability to recognize the face from one's own age compared with other age groups. Here we examined whether an own-age advantage occurs for faces sex categorization. We examined 7- and 9-year-olds' and adults' ability to correctly categorize the sex of 7- and 9-year-olds and adult faces without external cues, such as hair. Results indicated that all ages easily classify the sex of adult faces. They succeeded in classifying the sex of child faces, but their performance was poorer than for adult faces. In adults, processing time increased, and a response bias ( male response) was elicited for child faces. In children, response times remained constant, and no bias was observed. Experience with specific category of faces seems to offer some advantage in speed of processing. Overall, sex categorization is more challenging for child than for adult faces due to their reduced sexual dimorphic facial characteristics.