Abstract: The present study aimed to replicate Kessler and McKenna’s (1978) ethnomethodological study that investigated how an individual attributes gender to a person. By administering figures depicted on overlays (Overlay Study), Kessler and McKenna found that the penis more than the vulva and the male sexual characteristics more than the female ones were significantly more salient in the gender attribution process. From all this, their adage is: “See someone as female only when you cannot see them as male.” Taking as a model Kessler and McKenna’s Overlay Study, we administered to 592 adults 120 new digital stimuli elaborated on realistic frontal images of human nudes to verify if the previously obtained results would be confirmed by using more realistic images. We found that the participants attributed male gender 86% of the time when the penis was shown, but only attributed female gender 67% of the time when the vulva was shown. All findings had strong statistical significance, confirming the findings of the Overlay Study that the penis makes the difference in gender recognition. Beyond an ethnomethodological approach, we have interpreted and discussed our results from the outlook of evolutionary and cognitive psychology and cognitive neuroscience, concluding that the cultural stereotypes and prejudices that affect gender attribution might not just be a mere cultural product, but rather the consequence of evolved cognitive biases.
We aimed to replicate Kessler and McKenna’s (1978) Overlay Study, which administered stylized drawings of the human body, by using realistic images taken from pictures of human models. We expected to find confirmation that primary sexual characteristics (genitals) would determine gender attribution (male/female) more than secondary/gender-linked sexual characteristics, and that male sexual characteristics would determine gender attribution more than female sexual characteristics, with a significantly stronger effect of the penis compared to the vulva, ceteris paribus. The results have disconfirmed the null hypothesis and substantially reconfirmed the results obtained in the previous Overlay Study. When the penis was shown in a picture, the participants attributed male gender 86% of the times when the penis was shown, but only 67% attributed female gender when the vulva was shown. In other words, female attribution when the vulva appeared in a human picture was about 1:200 (female/male) compared with male attribution when the human body showed a penis. Furthermore, the participants attributed male gender to neutral stimuli (3 male and 3 female variables) five times more often when the penis was displayed than when the vulva was shown. All findings had a strong statistical significance, leading us to substantiate the Kessler and McKenna’s (1978) adage, “See someone as female only when you cannot see them as male” (p. 158). Female gender attribution appears to be triggered only when every other male cue has been excluded. In other words, gender cues are neither equally powerful nor salient. Therefore, all other things being constant, a female cue is recognized as such only in the absence of male cues. Whereas a male gender cue most likely equals male, a female cue equals female with much less probability. In this sense, we have defined above the Freudian and ethnomethodological attribution of female gender as an apophatic process.
Unlike Kessler and McKenna’s ethnomethodological approach, which they used to explain the gender attribution as a purely cultural construction, we also use the interpretative model of evolutionary psychology, which has spread after the Overlay Study, mainly by Cosmides and Tooby (Cosmides, 1989; Cosmides & Tooby, 1992; Tooby & Cosmides, 1992). Evolutionary psychology overcomes any dichotomy between nature and nurture or biological and cultural. Psychological/cognitive mechanisms/processes and cultural products co-evolve, so that environment forms; environment is necessary for the emergence and activation of each mechanism/process. Therefore, given that behavior requires evolved psychological mechanisms combined with environmental input in a causal chain, beyond the ethnomethodological interpretive model that makes use of the cultural construction of gender (patriarchal and phallocentric), we provide an explanation of our findings from an evolutionary psychology approach as cognitive adaptations that guide human behavior to adapt to the environment.
Seen from a less dichotomous and more dialogic and circular approach to interrelations between nature and culture, gender attribution is neither just pre-programmed nor simply derived from the social environment. The fact that, in a phallocentric culture, a penis makes somebody a male and not a female, as Freud’s psychological theory of human development also taught, does not negate the fact that these evolved cognitive adaptations were guided by an adapted mind (Tooby & Cosmides, 1992). There is no doubt that, in patriarchal cultures, the female role is derived from the space left free by the male role, though still under patriarchal control. So we can read biological cues as cultural: “the only sign of femaleness is an absence of male cues” (Kessler & McKenna, 1978, p. 152). However, this does not contradict that what culture has expressed, strengthened, sedimented, socially stratified, and handed down through cultural products and memes may have evolved from cognitive processes that have guaranteed human survival (Barkow, 1992; Buss, 2001; Carruthers et al., 2006; Ji & Yap, 2016; Lumsden & Wilson, 1981). In case of ambiguity or complexity in the detection of gender cues, a cognitive bias has saved humans from a risky encounter with an aggressive male (Dimberg & Öhman, 1996; Dimberg et al., 2000; Navarrete et al., 2009). This is consistent with our data about the ability to recognize a masculine face as a face of a man—this attribution is 1000 times more likely than attributing a feminine face to a woman—or about the certainty in gender attribution, according to which participants stated they were less certain when they had to attribute female gender to a picture (as opposed to male gender). This finding would also rule out the null hypothesis for the second assumption (H2). A male face is an excellent predictor of male gender attribution (Jackson, 1992; Simpkins, 2014) and, if associated with the penis, as previously found by Kessler and McKenna (1978), can overshadow all other female cues (face or vulva).
Unlike Kessler and McKenna’s study, the present investigation also examined the pleasantness of the trans-images, that is, those with a balanced co-presence of male (= 3) and female (= 3) variables (Supplementary material, Tables S1 and S2). Of the participants, 98% found unpleasant the 20 neutral gender pictures, significantly more than how they felt about other pictures with unbalanced gender sexual characteristics. This can be explained in several ways that are not necessarily mutually exclusive. These cross-sex/gender/clothing pictures, more than others, might recall the image of transsexual individuals, thus triggering the widespread sense of transphobia (Hill & Willoughby, 2005; Killermann, 2017). It is equally likely that the strong ambiguity of these pictures could have triggered the so-called uncanny valley phenomenon, that is, the emotional response to a humanoid whose resemblance to a human being is confusing (Mori, 1970). These 20 stimuli, more than others, confused respondents because they did not allow a clear dichotomous gender attribution (humanoid: human = picture with balanced co-presence of gender characteristics: picture with non-balanced co-presence of gender characteristics; MacDorman et al., 2009). In addition, processing facilitation increases positive affect (Winkielman & Cacioppo, 2001), also described as the pleasure of cognitive ease (Kahneman, 2011) or feeling of familiarity (de Vignemont, 2018). This uncanny valley/transphobia effect, caused by neutral stimuli, can also be explained using, once again, signal detection theory (Spackman, 1989). The perturbing effect (uncanny valley/transphobia) occurs when an individual cannot recur to a simplifying heuristic—to a rule of thumb, as (Kahneman, 2011) wrote—to make a difficult judgment about the gender of a person, due to the co-presence of salient male and female cues of sexual characteristics, for example, people with intersex or transsexual characteristics (in our study, the neutral stimuli).
Characteristics of the Sample
Based on the results, the main sociodemographic variables of the participants, treated independently, did not significantly affect the responses on the Adult Gender Attribution Test. The sample was mostly young adults (about 19 years of age), certainly due to the fact that the recruitment took place on a university campus. Of the participants, 97% identified themselves in the male/female binary gender mode among Facebook’s 58 gender options. We have no official data on the transgender population in Italy: While we are writing this work, the first demographic survey is underway in Italy (see: www.studiopopolazionespot.it/). According to the demographic study on transgender and gender non-binary people in the United States by (Nolan et al., 2019), the range of estimated prevalence is 0.39–2.7%. Therefore, transgender non-binary people among the participants of this study (2.9%) seem to be slightly higher than the U.S. range. Less than 1% of males (sex assigned at birth) did not see/define themselves as a man, choosing another gender identity. By contrast, 3% of females did not feel like a woman; this was significantly different from males. The males had remained more “loyal” to their cisgender identity, that is, their sex assigned at birth aligns with their gender identity and gender expression (Killermann, 2017), compared with their female counterparts. Put another way, “I’m a male, so I’m a man.” This increased female trans-sexuality that appears in our sample is in line with what has already been found in several studies (Baumeister, 2000; Lehmiller, 2018): Women’s sexual behavior is more variable (flexible) than men’s over the course of their lives.
Regarding sexual orientation, our sample does not seem to match the survey data reported by the National Institute of Statistics (ISTAT, 2012) on the homosexual population. ISTAT found that about 2.4% of the Italian population declared themselves to be homosexual or bisexual and 77% heterosexual. Conversely, 84% of our participants affirmed themselves to be exclusively heterosexual and 4% homosexual or bisexual. The difference can be explained by the fact that the survey of sexual orientation was conducted with different metrics. In fact, ISTAT percentages refer to a breakdown of the population into categories that include both sexual orientation (hetero, gay, and bisexual) and gender identity (transgender and other identity).
Regarding religious affiliation, the Catholic affiliation of participants was lower (53%)—but higher than no religion (42%)—than the Italian average among a student population aged between 18 and 34 (respectively, about 61% and 36%), according to Ipsos Public Affairs (2017). Addressing a sexually explicit issue seems to attract more people without religious affiliation and with a left-wing political orientation (33%).
Limits of the Study
We will discuss what we consider to be the most relevant limitation of the study below.
- 1.
Generalizability of the results (Kukull & Ganguli, 2012). Although the research is based on a large number of participants, due to the characteristics of the sample (e.g., the prevalence of university students) and the recruitment context (i.e., a university campus), the results may not be generalizable, for example, to the Italian population.
- 2.
Social desirability (Babbie, 2010). Whenever we ask people for information, they answer through a filter of what will make them look good. This is especially true when participants are asked to respond to extremely sensitive topics such as sexuality. For example, a respondent was convinced that the test was intended to measure attitudes toward transgender people—despite the fact that, to prevent any misunderstanding about the purposes of the research, the information sheet expressly stated that the study did not concern transphobia, “gender theories,” or queer theories. That person could have answered the question, “How pleasant is the picture you have just seen?” with a higher score of pleasantness, so as not to appear as a moralistic transphobic, intolerant person. This limit of explicit measures on sexuality (Baumeister, 2000) could be overcome by using procedures of implicit gender attribution (Wittenbrink & Schwarz, 2007), knowing that gender attribution is processed below the level of consciousness (subliminally; Ito & Urland, 2003; Sapolsky, 2017).
- 3.
Ecological experimental context. Although the purpose of our study was to replicate the Overlay Study with more realistic stimuli, this does not mean that the environmental setting and nature of the stimuli were entirely ecological. For example, a more ecological gender-attribution process could have been observed in how an individual attributes the gender of a live person in their presence. Now, if it is true that gender attribution is processed by an evolved mental module to solve a specific adaptive problem (e.g., recognition of an aggressive male), the specificity of these cognitive modules is extremely dependent on the context (Fodor, 1983). As evolutionary psychology teaches us, an innate psychological mechanism is not equally effective in solving a logical abstraction of the same problem, for example, in solving the same problem through the solution of abstract syllogism (Cosmides, 1989; Cosmides & Tooby, 1992, 1994).
- 4.
Cross-cultural method. The presented experimental design did not include a comparison between samples from different cultures. However, comparing different cultures would allow us to investigate whether the process of gender attribution can be ascribed more to human universals (Atran, 1998; Brown, 1991)—that is, to the effect of evolved psychological mechanisms—rather than to the influence of memes.
- 5.
Replication of the Overlay Study. We decided to exclude in the Adult Gender Attribution Test one question that was included in the original study: “How would you change the figure to make it into the other gender?” (Kessler & McKenna, 1978, p. 146). This question should have been presented below each of the 120 stimuli and would have enabled us to analyze relevant qualitative information. Our choice was dictated by the fact that we did not want to increase the time needed to complete the test, especially because it was administered online (which would have compromised the reliability of the data we wanted to collect).
During the review process of the present study, one of the reviewers pointed out to us that we should have acknowledged in some way that sex is not binary, as follows:
Some people with XY chromosomes never develop a penis because they have an insensitivity to androgens. Some people are intersex. Some have too many or too few sex chromosomes. And as we learn more about the variations in the biology of people that impact their sex and gender identity it is important to understand sex/gender as cultural. If a penis is what makes someone male, then are sex reassignment surgeries to either add a penis (for transgender men) or remove a penis (for transgender women) more common than the addition or removal of a vulva?
We fully agree with the reviewer’s assertion that sex is not binary, and that reality (biology) is more complex than how psychological mechanisms, evolved to solve adaptive problems related to survival, lead us to think fast (about fast and slow thinking, see Kahneman, 2011). We feel differently about gender transition. Counterintuitively, in our view, a female-to-male transition is easier than a male-to-female transition for two patriarchal cultural reasons: (1) the male androcentric model is socially better defined and aspired to than the female model and thus easier to adopt; and (2) a male-to-female transition involves a more serious transgression of power hierarchies than vice versa and thus is socially more difficult to accept. However, this issue is far beyond the scope of this study and deserves empirical verification that this study does not provide.