1. Be aware of your Assumptions.
Avoid gender-biased assumptions about a priori sex differences in animals, and reflect upon “taken-for-granted” views of female or male traits in each stage of the scientific process.
- a. Gender-biased assumptions may have an impact on different stages of the scientific process and a critical reflection on a priori sex differences is thus recommended in all stages. Gender-biased assumptions may appear when conceptualizing ideas, making predictions, and framing theories. These assumptions often appear in introductory sections, where sex differences in animals often appear as general trends without sufficient literature support (for example, “competitive” males and “choosy” or “caring” females—when, in fact, both sexes can display these behaviors). It is crucial to be open to the diversity of outcomes in experimental and theoretical research, especially the diversity of what males and females of various species do in nature. We argue that even well-supported general trends may encounter exceptional behaviors in nature that should not be overlooked. We argue further that differences—as well as similarities—between and across the sexes is important to present in qualitative and quantitative ways (for balanced examples, see Clutton-Brock 2007; Rosenthal 2017; Hare and Simmons 2019).
- b. In data collection and experimental design, use “naïve” experimenters (i.e., experimenters uninformed about predictions, treatments, and sex of the organism), whenever possible, to avoid introducing bias. This is especially important in behavioral studies, where observers may carry unconscious assumptions about expected male or female behaviors. Also be aware that, when collecting data, researchers may pay more attention to findings that confirm what they believe to be true. Dominant animal model systems may prompt confirmation biases (Zuk, et al., 2014).
- a. Provide scientific support for the assumptions made about the sexes, and acknowledge and address critical scientific debate that exists in the literature. Avoid fallacies, such as “appeal to authority” and confirmation bias, that may limit the ability to recognize diversity and variation among the sexes. For example, in evolutionary biology, the long established argument that female and male sexual traits and behaviors result from anisogamy, i.e., the fusion of a large egg and small sperm—as put forth in the Bateman-Trivers paradigm (Bateman, 1948; Trivers, 1972)—is an appeal to authority. Researchers should also openly present critical debates surrounding these arguments (Snyder & Gowaty, 2007; Tang-Martinez, 2005).
- b. When designing an experiment, present your arguments for a chosen design, especially when only one sex is studied or when the methods differ for the sexes. This will allow the readers to assess whether the design embeds gender-biased assumptions. Where feasible, measure the same parameters in the same way in all sexes. If only one sex is studied, specify which sex and provide the rationale for why. When measuring sex-specific traits, reflect openly about the relevance and the comparability between sexes.
Be aware of and careful in the choice of words, metaphors, and anthropomorphic terminology in relation to sex, as they may carry normative implications and may mislead a reader into gender-biased assumptions (see Method: Rethinking Language).
- a. Language itself can be gendered (Beldecos et al., 1989), and its use is a powerful tool that requires care and precision. It has been well documented, for example, that, when describing similar behaviour, female animals often are described as passive while males are described as active (Bertotti Metoyer & Rust, 2011; Karlsson Green & Madjidian, 2011).
- b. Language can embed metaphors that carry normative implications beyond what the evidence may show (Hankinson Nelson, 2017). To guard against this, use descriptive, neutral, and operational language, especially where metaphors or shorthand terms rely on readers’ cultural expectations—see Table 1. A simple self-test can be to switch male and female terms. If the meaning of the sentence is changed beyond the simple change of sex, the wording may be gender-biased.
| Anthropocentric terminology | Recommended alternatives |
| “Homosexual” (MacFarlane, Blomberg, & Vasey, 2010) |
Use the descriptive term “same-sex” (Scharf & Martin, 2013) |
| “Sex-roles” or “reversed sex-roles” (e.g. Forsgren, Amundsen, Borg, & Bjelvenmark, 2004; Hare & Simmons, 2019; Lehtonen, Parker, & Schärer, 2016) | Use “courters” and “choosers” as operational descriptors, independent of sex (Rosenthal, 2017) or just describe operationally what females and males do without ascribing them “sex-roles” (Ah-King & Ahnesjö, 2013) |
Be clear and careful when generalizing results. Scientific rigor should be applied to: 1) ensure representative sampling of the sexes; 2) unbiased trait measurements; and 3) evaluation of alternative hypotheses.
- a. Both female and male animals should be used in representative numbers for data collection, and data should be analysed by sex (Shansky, 2019). Females have historically been understudied. In the study of animal genitalia, for example, female genitalia remains understudied (Ah-King et al., 2014). Studies can be designed to investigate the previously underrepresented sex, where relevant.
- b. Studies done in one sex should not be generalized to other sexes.
- c. Explanatory frameworks should not exclude less common findings in a particular sex; rather variations should be acknowledged. Sexual selection research, for instance, has historically focused more on males than females and focused on extravagant traits used in mating competition (both competition for access to mating partners and competition to be chosen as mating partners). This asymmetry can be seen in textbooks, where illustrations feature a higher number of male than female animals (Fuselier et al., 2018). Recent literature, however, has shown sexual selection is not confined to one sex (Clutton-Brock, 2007; Hare & Simmons, 2019).
Works Cited
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