Gendered Fitness Interests: A Method Partitioning the Effects of Family Composition on Socio-Political Attitudes and Behaviors

Abstract

Whereas most people are biologically either male or female, their genetic interests are almost never aligned with just their own sex. Drawing on the evolutionary theory of inclusive fitness gained through relatives, we suggest it is possible to partition the effects of kin on fitness into those that derive from female versus male relatives. We argue that the balance of these femaleand male-derived effects, which we call 'Gendered Fitness Interests' (GFI), might influence human behavior, especially the adoption of socio-political attitudes regarding issues with a gendered dimension. Our proposal builds on previous conjectures within evolution, as well as observations from both within and beyond the evolutionary sciences that parents' socio-political views covary with the sex of their children, and the numbers of relatives of each sex. Further, it is consistent with the relatively small average differences between women's and men's socio-political positions.Using simulated data, we outline a method for partitioning GFI, and derive the testable predictions that the GFI component of women's and men's socio-political attitudes will converge with age, and with larger family sizes. Our proposal does not replace or falsify other theories of sex differences SOCIO-POLITICAL ATTITUDES AND GENDERED FITNESS INTERESTS 2 and similarities, but it does formalize a previously underappreciated component of variance in traits and attitudes with a gendered dimension. In this respect, it may be generally useful in resolving the complex origins of gendered behavior, and the primacy of an individual's gender identification (including but not limited to biological sex) as a fixed and distinctive part of their socio-political identity. SOCIO-POLITICAL ATTITUDES AND GENDERED FITNESS INTERESTS

He for she? Variation and exaggeration in men's support for women's empowerment in northern Tanzania

“…This is naive on several fronts. First, inclusive fitness interests are spread among kin of each sex (Brooks & Blake, 2019). In other words, a man must consider not only the consequences of WE for himself, but also his mother, sisters and daughters (and likewise a woman's attitudes will be influenced by considering their father, brothers and sons).…”

“…In other words, a man must consider not only the consequences of WE for himself, but also his mother, sisters and daughters (and likewise a woman's attitudes will be influenced by considering their father, brothers and sons). As such, we can anticipate that men and women's attitudes will often converge, and potentially be sensitive to individual variation in the gender composition of kin, of which there is some limited evidence (Borrell-porta et al, 2019;Brooks & Blake, 2019;Oswald & Powdthavee, 2010). Second, men's fitness requires effective cooperation with women both as sexual partners and in rearing offspring.…”

Male descendant kin promote conservative views on gender issues and conformity to traditional norms

“…Recent theoretical and empirical work has proposed that an individual's sociopolitical attitudes will track ‗Gendered Fitness Interests' (GFI); the extent to which the individual's future genetic fitness is more likely to be a product of the reproductive success of living female versus male relatives (Blake et al, 2018;Brooks and Blake, 2021). This approach is grounded in both inclusive fitness (Hamilton, 1963;1964a, b) life history perspectives (Roff, 1992;Stearns, 1992).…”

“…probability of sharing a given allele by descent) and their residual reproductive value (i.e. their age-based potential for future offspring; Brooks and Blake, 2021). Some initial work has found evidence that GFI predicts social attitudes.…”

Gendered fitness interests: A method partitioning the effects of family composition on socio-political attitudes and behaviors

“…Observations from our similar model are consistent with Alexander's conjecture. Spouses are well known to evince highly similar socio-political attitudes (Bouchard 2009, Alford et al 2011. Most of that similarity, however, is already present early on in the relationship (Alford et al 2011), and does not appear to increase with the duration of the relationship (Martin et al 1986).…”