“Sociosexuality from Argentina to Zimbabwe: A 48-nation study of sex, culture, and strategies of human mating” delivers on its title. By combining empiricism and careful hypothesis testing, it not only contributes to our current knowledge but also points the way to further advances.

Extending the findings of this work: Tribal peoples need study. Monogamy as marital institution and monogamy as sociosexual orientation must be separated. Sociosexuality must be considered as an aspect of somatic as well as reproductive effort; third-party interventions in sociosexuality need attention; and multiple sociosexual orientations, with frequency-dependent fitness payoffs equal at equilibrium, need to be modeled.

we propose a way to achieve across-population sharing within the authors' model in a way that is plausibly in accordance with human evolution, and also a simple way to capture ecological structure. finally, we briefly reflect on the model's scope and limits in modeling linguistic communication.

Men and women report having significantly different numbers of sexual partners, which is impossible in a large sample. Schmitt's target article is no exception. This focuses discussion on the nature of the samples, their heterogeneity, and the locale they are drawn from. Further, we query how humans determine, for example, sex ratio, in the context of large numbers.

to vallortigara & rogers's (v&r's) evidence of everyday directional asymmetries in the natural environment of a variety of species, we offer one more example for human beings. it is the bias for holding an infant on the left side, and it illustrates several themes in the target article.

Schmitt's study provides strong support for sexual strategies theory (Buss & Schmitt 1993) – that men and women both have evolved a complex menu of mating strategies, selectively deployed depending on personal, social, and ecological contexts. It also simultaneously refutes social structural theories founded on the core premise that women and men are sexually monomorphic in their psychology of human mating. Further progress depends on identifying evolved psychological design features sensitive to the costs and benefits of pursuing each strategy from the menu, which vary across mating milieus. These design features, like many well-documented mating adaptations, are likely to be highly sex-differentiated.

the debate of nativisim versus empiricism is over the relative importance of evolutionary versus ontogenetic mechanisms. this is mostly seen today as a false dichotomy. the synthesis of these positions provides a modern viewpoint of grounded category formation. this combined view places equal importance on feedback between these levels in guiding development, and is more appropriately compared to culturalist positions.

extrapolation of steels & belpaeme's (s&b) results show that colour is a culturalist category. populations will only share the category of colour if it is built into the system. if “left to themselves” different populations may or may not stumble on the colour category. populations that do not share a colour category may still be able to communicate in a wide variety of environments.

Schmitt finds that national sex ratios predict levels of sociosexuality, but how we should interpret this result is unclear for both methodological and conceptual reasons. We criticize aspects of Schmitt's theorizing and his analytic strategy, and suggest that some additional analyses of the data in hand might be illuminating.

Schmitt has equivocated about the underlying psychology of sociosexuality, but from the data presented in the target article, it would appear that he has drawn out the underlying cognitive architecture. In this commentary, I describe this architecture and discuss two emerging hypotheses about heterosexual and homosexual male sociosexuality.

an evolutionarily stable strategy (ess) may apply to characters expressed across species for predation and feeding, because these characters are conservative. however, the evolution of complex, polymorphic behaviors is more difficult to define as an ess. lateralization may be selective for certain simple traits, but lateralization of complex traits is likely the result of coadaptation of otherwise non-lateralized features.

i suggest that a communicative context that has the potential to establish and maintain a shared advantage of behavioral lateralization should be identified in the domain of sexual selection, specifically in the interactions that individuals exploit to assess the fitness of potential mates.

Schmitt's findings provide little evidence that sex differences in sociosexuality are explained by evolved dispositions. These sex differences are better explained by an evolutionary account that treats the psychological attributes of women and men as emergent, given the biological attributes of the sexes, especially female reproductive capacity, and the economic and social structural aspects of societies.

Previous research has suggested that offspring sex ratio may be influenced by the actions of prenatal sex steroids, principally androgens. The relative length of the second (index finger) to the fourth digit (ring finger) has been reported to be a proxy to prenatal testosterone levels. This trait is sexually dimorphic, such that males display a significantly lower 2D:4D ratio (indicating higher testosterone exposure), and this dimorphism appears robust across different populations. We suggest that digit ratio (2D:4D) may form a useful marker to help explain variation in sex ratio and sociosexuality.

the general structure of steels & belpaeme's (s&b's) central premise is appealing. theoretical stances that focus on one type of mechanism miss the fact that multiple mechanisms acting in concert can provide convergent constraints for a more robust capacity than any individual mechanism might achieve acting in isolation. however, highlighting the significance of complex constraint interactions raises the possibility that some of the relevant constraints may have been left out of s&b's own models. although abstract modeling can help clarify issues, it also runs the risk of oversimplification and misframing. a more subtle implication of the significance of interacting constraints is that it calls for a close relationship between theoretical and empirical research.

sunstein argues that heuristics misguide moral judgments. principles that are normally sound falter in unusual cases. in particular, heuristics generate erroneous judgments about regulation of risks. sunstein's map of moral reasoning omits some prominent contours. the simple heuristics he suggests neglect a reasoner's attempt to balance the pros and cons of regulating a risk.

The target article effectively assesses multiple hypotheses for human sexuality, demonstrating support for a complex, integrated perspective. However, care must be taken when extrapolating human universal patterns from specific cultural subsets without appropriate ethnographic contexts. Although it makes a strong contribution to the investigation of human sexuality, the basal reliance on a reductionist perspective constrains the full efficacy of this research.

Schmitt recognized that research is needed to identify other factors associated with sex ratio and with sociosexuality that may explain cross-cultural variation in sexual behavior. One such factor may be the risk of sperm competition. Sperm competition theory may lead us to a more complete explanation of cultural variation in sexual behavior.

steels & belpaeme's (s&b's) simulations contain all the right components, but they are put together wrongly. color categories are unrepresentative of categories in general and language is not merely naming. language evolved because it provided a powerful new way to acquire categories (through instruction, rather than just the old way of other species, through trial-and-error experience). it did not evolve so that multiple agents looking at the same objects could let one another know which of the objects they had in mind, co-coining names for them on the fly.

this article proposes a number of models to examine through which mechanisms a population of autonomous agents could arrive at a repertoire of perceptually grounded categories that is sufficiently shared to allow successful communication. the models are inspired by the main approaches to human categorisation being discussed in the literature: nativism, empiricism, and culturalism. colour is taken as a case study. although we take no stance on which position is to be accepted as final truth with respect to human categorisation and naming, we do point to theoretical constraints that make each position more or less likely and we make clear suggestions on what the best engineering solution would be. specifically, we argue that the collective choice of a shared repertoire must integrate multiple constraints, including constraints coming from communication.