In this study, we often associate gender with sex/biological categories (male/female or penis/vulva), as we do in the title. We use the term gender (Bazarra-Fernandez, 2012; IPSOS, 2020; Krieger, 2003) because even sex variables are not understood in the objective, physical dimensions, but always subjective, as cognitive representations (Ito & Urland, 2003, 2005; Knutson et al., 2007). From this point of view of cognitive psychology, a primary sexual characteristic makes no difference, if not semantic, from a secondary one or from male, female, or unisex clothing (Carruthers et al., 2006; Tooby & Cosmides, 1992). All are ways of constructing reality (Olivetti Belardinelli, 1973). Our purpose is to investigate what influence each of these sexual characteristics has on cognitive processes of gender attribution (individual representations), not what determines an individual’s sex (biological). These cognitive processes and their products, the representations, are the outcome of determinants both internal to the human organism and external, often defined in the nature–culture relationship. This relationship will also be evident in the present study, where the representation of gender will be given by the outcome of sexual characteristics that will fluctuate from those more typically natural/biological to those more typically cultural, such as clothing.
Neuroscience studies have highlighted that our brains form us/them dichotomies (based on differences of social status, race, gender) with a staggering speed (Ito & Urland, 2003; Sapolsky, 2017). We know that a 50-ms exposure to the face of someone of another race activates the amygdala, while failing to activate the fusiform face area as much as same-race faces do—all within a few hundred milliseconds (Sapolsky, 2017). Similarly, the brain groups faces by gender or social status at roughly the same speed (Ito & Urland, 2003).
From an evolutionary perspective, it is understandable that there is the need for prompt recognition of us/them with respect to gender. We know that a fear emotional reaction is more likely to be conditioned by an angry male face than by a female face, and by an adult face than by a childish face (Dimberg & Öhman, 1996; Dimberg et al., 2000). Consistent with the evolutionary perspective, this mechanism has developed to avoid what is the greatest danger: an (angry) adult male. In addition, because people rely on simplifying the decision-making process, especially in cases of ambiguity, time pressure, or complexity (Kahneman, 2011; Korteling et al., 2018; Rachlin, 2003; Shah & Oppenheimer, 2008; Tversky & Kahneman, 1974), they revert to heuristic strategies. The human being must at all costs avoid confusing a male for a female, rather than the opposite. Lowering one’s defenses, because one has assumed to be in the presence of a female rather than a male, is more likely to cost one’s life compared to confusing a female with a male. For this reason, male sexual characteristics take on the function of attention targets in gender (signal) detection (Spackman, 1989). In case of ambiguity in the detection of gender cues, humans have had to avoid at all costs a false negative (detecting a female when it is male) because it is definitely riskier than a false positive (detecting a male when it is female). Furthermore, as the applied psychometry has demonstrated (Chadha, 2009), the false negative error (i.e., type I error rejecting the null hypothesis [H0] when it is true: detecting a female when there are male characteristics) and a false positive (i.e., type II error accepting H0 when it is false: detecting a male when there are no male characteristics) are mutually exclusive (inverse correlation). This type of correlation can only be justified if the two errors are affected by the same condition, that is, in the case of gender detection, the presence/absence of male sexual characteristics, but not in case the conditions were different, namely the presence/absence of male and female sexual characteristics.
As suggested by Navarrete et al. (2009), gender categorization might act as a heuristic cue for the potential for danger solely when the exemplars are male. Such an evolved cognitive mechanism occurs both in males and females. In fact, for all individuals (e.g., infants, females), the risk of socializing with a male is greater than with a female, because male individuals tend to be physically stronger and much more aggressive. In this view, to mistake a female when it is a male is potentially more dangerous than the opposite for human survival. Thereby, a subtraction is applied to the higher danger condition (male) to get to the lack-of-danger condition (non-male). In other words, to survive, it is much more convenient to make a wrong female than a male gender attribution. These errors of judgment are determined by cognitive mechanisms evolved by natural selection that “occurred despite the fact that subjects were encouraged to be accurate and were rewarded for the correct answers” (Tversky & Kahneman, 1974, p. 185). As an automatic evolved mechanism, the male pre-judice works as a cognitive constraint within which culture has been modeled and passed on by memes (Blackmore, 1999) of what we now call patriarchalism, androcentrism, and phallocentrism, by the means of imitation, education, religion, philosophy, and politics (Bem, 1993; Ranke-Heinemann, 1990). Although the functioning of the cognitive bias is “not attributable to motivational effects such as wishful thinking or the distortion of judgments by payoffs and penalties” (Tversky & Kahneman, 1974, p. 185), the cultural context and parental milieu nonetheless provide that ecological niche where such automatic behavior is reinforced and rewarded, that is, the motivating power of stereotypes, myths, beliefs, and ideologies (Federici et al., 2019).
Going back in history, even Freud assumed—what we have seen above was demonstrated by modern cognitive neuroscience—the existence of a universal, fast, and quite reliable cognitive mechanism of gender recognition. As he taught: “When you meet a human being the first distinction you make is ‘male or female?’ and you are accustomed to making the distinction with unhesitating certainty” (Freud, 1932/1964, p. 113). According to Freud (1925/1959), around the age of five, children become aware of their sexual/gender identity by becoming aware that they either possess or do not possess a penis. The recognition that one has or does not have a particular set of genitals, for Freud, is tantamount to recognizing the gender to whom they belong. “I have a penis” means “I am a boy,” and “I do not have a penis” means “I am a girl.” In this theory, the gender identity is a genital (penis-centered) identity.
Freud’s thought, therefore, assumes an apophatic way (i.e., a negative way, involving knowledge obtained by negation) to know the female identity. A child does not know what a female is, but they know what the penis does. A female also does not know what she is, because she is nothing but a human non-man or not-having-phallus. Literally, the female is but an absence (for a review on apophasis, see Zalta, 2020).
Through an ethnomethodological study, the feminist gender psychologists Kessler and McKenna investigated the apophatic gender construction; they found that penis equals male, but vulva does not equal female (Kessler & McKenna, 1978). When nude human figures were shown to participants having a vulva, the other male characteristics remained more powerful and dominant in affecting participant’s gender attribution. Of all the gender characteristics, the penis was the most “powerful” (salient). The results highlighted that “‘[m]ale’ gender attributions increased from 69 to 96% when a penis was added [to the stimulus figure] (p. 151).” When Kessler and McKenna then asked participants how they would change the nude figures to make them of opposite gender:
[i]n changing a male to a female[,] 38 percent of the participants mentioned removing the penis, but only one percent said that it was necessary to add a vagina. When changing a female to a male, the findings are reversed. Thirty-two percent of the participants said that a penis needed to be added to make a male but only one percent said that the vagina need be removed. (p. 153)
The salience of the penis was also observed by Thompson and Bentler (1971) in a study where nude dolls with various combinations of male and female gender characteristics were shown to adults and children. According to their findings, the masculine doll minus the penis was still seen as very male, but in its presence the feminine doll with a penis could not be seen as female.
Although the salience of the penis, and therefore its absence, remains decisive in gender attribution, the process of gender categorization does not only take place when information on genital characteristics is available. Even in the absence of this information, gender attribution is an automatic process that ends in milliseconds: The gender of a face is processed within 150 ms, after social dominance (40 ms) and race (100 ms) (Ito & Urland, 2003; Rule et al., 2012; Sapolsky, 2017).
Another study we think is worth considering in this regard, and that largely refers to the assumptions proposed by Kessler and McKenna (1978), is that carried out by Simpkins (2014). Using an ethnomethodological model, the study proposed to show participants images of parts of real human faces, created by photographing 28 people who varied by gender, ethnicity, and age, on the grounds that the face is “usually the first source of information available about a person” (Jackson, 1992, p. 3). The study concluded with a significant disproportion between the times in which the participants attributed male gender to the stimuli compared to times in which they attributed female gender to the stimuli, combined with an attribution of gender for 99% of the binary cases (male/female). It is interesting to note that even the interviewees who had identified themselves as having a non-binary gender made attributions related prevalently to male or female gender.
The most recent study that replicated Kessler and McKenna’s study used eye tracking on digital reproductions of original stimuli (Wenzlaff et al., 2018). Participants gazed longer at the head, chest, and genital areas of all the stimuli. Of note, they attributed female gender when a penis was present. It was associated with longer total dwell time than with male gender with a vulva shown. This is indicative of higher cognitive effort and more difficulty ignoring the penis as opposed to the vulva. Wenzlaf et al. concluded that the penis is a special cue in this attribution process.
The present study aims to replicate Kessler and McKenna’s (1978) ethnomethodological study with more realistic stimuli. In addition, if the results are confirmed, our study aims to go beyond an exclusively ethnomethodological interpretation of the data, using a more multidisciplinary approach, based on recent assumptions provided by cognitive neuroscience, cognitive psychology, and evolutionary psychology. Ethnomethodology is the study of how social order is produced in and through processes of social interaction (Garfinkel, 1967, 1974). According to the ethnomethodological perspective, “the gender is a social construction and a world of two ‘sexes’ is a result of the socially shared, taken-for-granted methods which members use to construct reality” (Kessler & McKenna, 1978, p. vii). As already defined above, our use of “gender” is not from an ethnomethodological perspective, but from a psychological one. We observe the male/female attribution as a product of a cognitive process, that is, as a phenomenological datum (gender), not a biological characteristic (sex). Like any cognitive process, this does not preclude that it may also be affected by social determinants, nor that the biological determinants were irrelevant.
In the following section, we will present the original experimental design (Overlay Study) of Kessler and McKenna (1978), from which we have developed our study.
If human figures with ambiguous sexual characteristics (not immediately definable as male or female and therefore indicated by us as neutral) are shown, and if adult individuals are asked to determine such figures’ gender, according to common sense, one would expect that 50% of the participants would assign a “male” gender attribution to the figures, and 50% would provide a “female” gender attribution. But this does not happen, as already demonstrated by Kessler and McKenna (1978). They investigated gender attribution by showing to 960 adults in person 96 different figures depicted on overlays. Each image displayed a combination of nine human physical characteristics and two sets of clothing (Fig. 1a, b). The eleven overlays depicted people with: long hair, short hair, wide hips, narrow hips, breasts, a flat chest, body hair, penis, vulva, unisex t-shirt, or unisex pants. These overlays were superimposed one on top of the other. When the overlays were placed on a human figure with a face that was not gender-specific, the result was a drawing of a figure with various combinations of typically male and female physical gender characteristics. Therefore, the figures could represent a nude human being, one wearing or a unisex t-shirt or unisex pants, or a unisex t-shirt and unisex pants. Kessler and McKenna’s basic hypothesis was that a figure with more female than male characteristics would be regarded as female and vice versa: One with more male than female characteristics would have resulted in a male attribution. Kessler and McKenna also wondered how the presence or absence of certain stimuli, particularly the genitals, would affect the attribution of participants. The participants were asked three questions: (1) “Does this figure represent a male or a female?”; (2) “Using a scale from 1 to 7, where 1 means ‘not at all sure’ and 7 means ‘very sure,’ how sure are you of the answer you gave previously?”; and (3) “How would you change the figure so that it becomes something else?” On the basis of their findings, Kessler and McKenna (1978) affirmed to have found a “schema” among “members of the West reality” that leads to gender attribution: “See someone as female only when you cannot see them as male” (p. 158).
Therefore, taking into account the material produced for the Overlay Study, we created new stimuli by using photographs, not drawings, to verify whether the results obtained previously (Kessler & McKenna, 1978) would be confirmed when using more realistic images. According to evolutionary psychology, evolved psychological mechanisms would have evolved to solve specific adaptive problems, not generic logical problems. Therefore, they are triggered by competent environmental stimuli (Cosmides & Tooby, 1992). In accordance with this theory, we preferred to propose more realistic stimuli than those in the Overlay Study, to observe more ecological cognitive responses. This meant that, with the adoption of two human models, one male and one female, we no longer had a human figure with a face that was not gender-specific on which to run plastic overlays. Therefore, compared to the Overlay Study, we introduced two additional variables: male face and female face.
The process of displaying the stimuli is detailed below in the Method section (see Phase and Procedure).
Condition should influence gender attribution as follows (H1):
The mean of the male gender attributions is higher than the mean of the female gender attributions, ceteris paribus.
In the presence of primary sexual characteristics (penis, vulva), a significant increase in the attributions of the gender consistent with the external genitalia (penis → male, vulva → female), compared to the presence of secondary sexual characteristics (e.g., body hair or breast), is expected.
In the presence of primary sexual characteristics (penis, vulva), a significant increase in the attributions of gender consistent with the external genitalia (penis → male, vulva → female) is expected to occur, compared to when the genitals are covered (e.g., pants).
In stimuli where the penis is shown, the mean of male gender attributions is higher than when the vulva is shown.
These four hypotheses are elaborated on the base of Kessler and McKenna’s (1978) Overlay Study. For sexual characteristics, we mean them in the most common sense: primary are sex organs or those characteristics that are used to establish the sex of human beings at birth; secondary are those developed later in life, usually during puberty (Weininger, 2005). The expected effects should replicate those found in the Overlay Study even using more ecological stimuli.
Secondary sexual characteristics in the face should influence gender attribution as follows (H2):
We expect the mean of male gender attributions of faces with male secondary characteristics to be higher than the mean of female attributions of faces with female secondary characteristics.
A person’s face and genitals are sufficient on their own to predict a person’s gender (Jackson, 1992; Kessler & McKenna, 1978; Simpkins, 2014), though not with the same compelling strength. Specifically, Kessler and McKenna found that a stimulus with a face with male secondary characteristics and vulva, as well as a face with female secondary characteristics and penis, predicted a male attribution. This means that the salience of the penis succeeds in nullifying the presence of a female face and that the salience of a male face succeeds in nullifying the presence of a vulva. The most interesting data from Kessler and McKenna’s study is that the strength of male features (face or penis) can obliterate all other female cues (face or vulva).
The condition should influence confidence in gender attribution as follows (H3):
The confidence in the attribution of the male gender is expected to be significantly higher than that of the female gender, ceteris paribus.
As introduced above with regard to the signal detection theory, assuming that gender attribution is determined by discrimination of the presence/absence of male characteristics (target), we assume that the use of a false positive (attribution of male gender) is perceived as more reliable than a false negative (attribution of female gender) in ambiguous stimuli (Navarrete et al., 2009).
Condition should influence pleasantness of the stimulus as follows (H4):
The degree of pleasantness of the stimuli is significantly lower in the co-presence of male and female sexual characteristics.
In stimuli where both male and female sexual characteristics are present (e.g., narrow hips, body hair, breast, and vulva), we assume that the pleasantness of the image shown as a stimulus could be influenced by implicit (Kanamori et al., 2020) and explicit (Hill & Willoughby, 2005) transphobic responses.