Sexual dimorphism refers to the morphological differences between male and female individuals, playing a critical role in mate selection and social interactions (Jones et al., 2010; Mori et al., 2022). Human sexual dimorphism cues, such as facial masculinity and femininity, reveal vital details about an individual’s reproductive potential, health, and threat potential (Thornhill and Gangestad, 2006; Rhodes et al., 2005; Little et al., 2011, 2015). Accurately identifying and interpreting these cues can significantly impact social judgments, including perceptions of attractiveness and dominance, which essentially influence mate preferences and competitive interactions between people (Han et al., 2022; Richardson et al., 2021).

Sexually dimorphic traits are one of the primary factors that contribute to facial attractiveness in women (Perrett et al., 1998). Understanding the role of sexual dimorphism in women’s facial attractiveness is important for uncovering the complicated mechanisms underlying mate preferences, social judgment, and the evolution of beauty standards (Little et al., 2011). Facial femininity is believed to signal aspects of reproductive health, genetic quality, and fertility in women (Thornhill and Gangestad, 2006; Rhodes et al., 2005). According to evolutionary theories, people are attracted to face features that suggest high genetic fitness because these traits may increase the likelihood of successful reproduction and offspring survival (Buss, 1989; Gangestad and Simpson, 2000). Research on the connection between women’s attractiveness and facial dimorphism has provided strong evidence regarding the impact of these characteristics on mate preferences and social judgment (Han et al., 2020; Little et al., 2011). Both men and women find women with more feminine facial features, such as softer curves, larger eyes, and smaller jaws, tend to be more attractive (Perrett et al., 1998; Jones et al., 2018; Little et al., 2011). These findings indicate that increased femininity in women’s faces enhances their general attractiveness and elicits positive social evaluations.

Sexually dimorphic cues on men’s faces significantly influence their dominant appearance (Richardson et al., 2021; Watkins et al., 2010a,b). Facial masculinity, characterized by prominent jawlines and brow ridges, is associated with perceptions of physical strength and dominance (Windhager et al., 2011; Richardson et al., 2021). These cues are important from an evolutionary perspective as they help people assess possible allies or competitors in social and competitive contexts. Men with more masculine facial features are judged as more dominant and formidable, which can have an impact on social hierarchy, mate preferences, and interpersonal interactions (Oosterhof and Todorov, 2008; Watkins et al., 2010a,b). These insights are supported empirically by studies such as those conducted by Watkins et al. (2010a,b) and Richardson et al. (2021), which show the intricate relationship between men’s facial dimorphism and social perception.

There are individual differences in the social judgment of sexually dimorphic cues. For example, shorter and less dominant men are more sensitive to dominance cues in other men (Watkins et al., 2010a,b). Specifically, it was observed that, during the task of selecting a dominant face from pairs of more or less sexually dimorphic male faces, shorter and less dominant men more frequently selected the face with increased masculine features (Watkins et al., 2010a,b). Moreover, it was found that men’s age and strength also influence their sensitivity to dominance when selecting dominant faces from sexually dimorphic male face pairs (Richardson et al., 2021). In addition, men’s testosterone levels may influence their judgment of the attractiveness of sexually dimorphic cues on women’s faces (Han et al., 2020). Given that men’s height, dominance, strength, age, and testosterone levels are associated with their formidability, it is reasonable to infer that men’s formidability may influence their sensitivity to the social perception of sexually dimorphic cues.

Although previous research has examined individual differences in social judgment (e.g., Watkins et al., 2010a,b; Richardson et al., 2021; Han et al., 2020), these studies have primarily focused on manipulating sexually dimorphic cues rather than investigating the specific traits that correspond to various social judgments (e.g., attractiveness and dominance). This limits our understanding of how individual differences in sensitivity to these cues may impact different aspects of social judgment. It is crucial to discern whether the observed variation in sensitivity to social judgment is primarily driven by sensitivity to sexually dimorphic cues or if the observed variation reflects a broader sensitivity to the psychological processes involved in social judgment. Surprisingly, to the best of the authors’ knowledge, no one has directly studied individual differences in recognizing and accurately perceiving sexually dimorphic cues.

The current study aimed to investigate individual differences in sensitivity to sexually dimorphic cues that signal gender. Men’s formidability may influence their social perception of sexually dimorphic cues (Watkins et al., 2010a,b; Richardson et al., 2021; Han et al., 2020). Body size is one of the important indicators of men’s formidability (Sell et al., 2009). In the current study, we investigated whether men’s body size influences their sensitivity to sexually dimorphic cues in gender perception. Given that taller and more dominant men are less likely to choose masculine male faces as the more dominant ones (Watkins et al., 2010a,b), we predicted that men with larger body sizes would be less sensitive to sexually dimorphic cues in a gender perception task.

Furthermore, we conducted an exploratory analysis to investigate whether men’s sensitivity to sexually dimorphic features would be influenced by facial sex (i.e., the sexual dimorphism of the face); however, this was not the primary goal of the current study. There is no existing literature on this topic, and we formulated our prediction as follows. Since misjudging other men’s sexually dimorphic features would carry greater costs (e.g., potential harm in intrasexual competition) for men than misjudging women’s sexually dimorphic features (e.g., missing a potential mating opportunity in intersexual selection), we predicted that men would be more sensitive to sexually dimorphic cues on men’s faces compared to those on women’s faces.

The responses in the gender judgment task were analyzed using mixed binary logistic regression in R version 4.3.2 (R Core Team, 2023) with lmerTest version 3.1.0 (Kuznetsova et al., 2017). To avoid multicollinearity, we analyzed the height, weight, and BMI values separately. In each model, the response (dependent variable, DV) was the binary choice (dummy coding for the face gender judgment: 0 = female, 1 = male). The height, weight, and BMI values were standardized by transforming them into z-scores. The face manipulation levels were coded as follows: 0.75 = 75% increased masculinization, 0.60 = 60% increased masculinization, 0.45 = 45% increased masculinization, 0.30 = 30% increased masculinization, 0.15 = 15% increased masculinization, 0 = sex neutral (i.e., androgynous faces), −0.15 = 15% increased femininization (i.e., 15% decreased masculinization), −0.30 = 30% increased femininization, −0.45 = 45% increased femininization, −0.60 = 60% increased femininization, and − 0.75 = 75% increased femininization.

In the height model, the DV was the response and the independent variables (IVs) were height (z-scored), manipulation levels, and their interaction. Random intercepts were participant ID and base face ID. Random slopes were specified maximally, following Barr et al. (2013) and Barr (2013). This type of analysis takes into account variations in the effects of shape manipulations across stimuli items (in this study, each base face/androgynous face; Barr et al., 2013).

The weight model and the BMI model were identical to the height model, except that height was replaced with weight (z-scored) and BMI (z-scored), respectively.

The present study aimed to investigate individual differences in sensitivity to sexually dimorphic cues that signal gender, with a particular focus on the influence of men’s body size. The results showed that men’s height, weight, and BMI were negatively associated with their sensitivity to sexually dimorphic facial features in gender perception. This finding indicates that men with larger body sizes are less sensitive to sexually dimorphic facial features. Moreover, the results also showed that men were more sensitive to the sexually dimorphic cues on male faces than on female faces.

Previous research on dominance in men has revealed that men with large body sizes are less sensitive to sexually dimorphic cues. Studies have shown that taller and more dominant men are also less sensitive to sexually dimorphic cues when judging other men’s dominance (Watkins et al., 2010a,b). Facial masculinity, which is strongly associated with perceived and actual dominance, may play a role in this relationship (e.g., Fink et al., 2007; Von Rueden et al., 2008; Boothroyd et al., 2007; Jones et al., 2010).

Men with larger body sizes are generally more formidable and attractive (Sell et al., 2009; Kurzban and Weeden, 2005). More formidable and attractive men may face fewer consequences for incorrectly judging sexually dimorphic cues in other men and women since they may be better equipped to handle the potential costs of engaging in aggressive conflict with other men and may have more opportunities to attract women. This leads to a reduced need for accurate perception of sexually dimorphic cues. Given that larger men are less sensitive to sexually dimorphic cues, they may be less sensitive to social cues related to sexually dimorphic cues. There is evidence that more formidable men are more likely to underestimate other men’s formidability (Fessler and Holbrook, 2013; Fessler et al., 2014) and tend to exhibit lower levels of psychological defensiveness toward other men, as reflected in their higher ratings of other men’s attractiveness and trustworthiness (Macapagal et al., 2011) and lower levels of jealousy (Buunk et al., 2008).

Furthermore, the current study also found that men displayed greater sensitivity to the sexually dimorphic cues on male faces than on female faces. This finding suggests that men might encounter greater intrasexual rather than intersexual selection pressures and consequently exhibit greater sensitivity to sexually dimorphic cues on men’s faces. This finding aligns with that of another study, which found that men’s interpretations of sexually dimorphic cues mainly serve to reduce the costs of making mistakes during intrasexual, rather than intersexual, interactions (Watkins et al., 2010b).

There are limitations in the current study. First, the finding that men exhibited greater sensitivity to sexually dimorphic cues on male faces compared to female faces was observed only when controlling for men’s body size. This finding means that the results should be interpreted with caution. Second, the current study only focused on men, limiting the generalizability of the findings to women. Future research should investigate women’s gender perception.

In conclusion, the present study extends our knowledge of how individual differences in sensitivity to sexually dimorphic cues affect perceptions of gender. The findings suggest that men with larger bodies are less sensitive to sexually dimorphic facial cues in gender perception. The present study also found that men showed greater sensitivity to sexually dimorphic features on men’s faces compared to women’s faces. Future studies may explore the underlying psychological mechanisms driving these findings.