Industrial melanism, according to the traditional explanation, amounts to niche construction since it involves changes in predation pressure. Indeed, it would be difficult to imagine selection without niche construction. This cannot be what Laland, Odling-Smee & Feldman mean. They offer convincing examples, but they should provide a better definition of “niche construction” to indicate how their view supplements traditional evolutionary biology.

Those who emphasize complexity must show how it can be studied productively. Laland et al.'s target article partially succeeds but at times gets lost in a sea of possibilities. I discuss the challenge of understanding complexity, especially with respect to multilevel evolution.

Studies of fluctuating asymmetry (FA) in relation to sexual strategies in humans provide the empirical basis for many arguments in support of good genes sexual selection theory. Many FA studies, however, are flawed by bias in experimental design, inconsistent statistical analysis, and the sloppy handling of data.

Fluctuating asymmetry is more a signal of genetic fitness than a marker observable only to the researcher. Hence, it has to be demonstrated that low FA is an honest signal of genetic quality; this has not been demonstrated in Gangestad & Simpson's otherwise useful review.

Our response contains a definition of niche construction, illustrations of how it changes the evolutionary process, and clarifications of our conceptual model. We argue that the introduction of niche construction into evolutionary thinking earns its keep; we illustrate this argument in our discussion of rates of genetic and cultural evolution, memes and phenogenotypes, creativity, the EEA (environment of evolutionary adaptedness), and group selection.

Women's preference for symmetrical men need not have evolved as part of a good gene sexual selection (GGSS) reproductive strategy employed during recent human evolutionary history. It may be a remnant of the reproductive strategy of a perhaps promiscuous species which existed prior to the divergence of the human line from that of the bonobo and chimp.

Gangestad & Simpson present an idealized model of human mate strategies based on rational economics and genetics that elides most social constraints on human sexuality. They do not deal with observable complexities of courtship nor with ambiguities in short- and long-term mating. The model successfully explicates a narrow set of premises, but cannot yet explain complex sexual behavior.

Human males are more polygamously inclined than females. However, there is substantial within-sex variation in polygamous inclinations and practices. This is acknowledged by Gangestad & Simpson but we pose the question: Is the target article's “strategic pluralism” pluralistic enough? In addition, we argue that the hypothesis that the female orgasm is an adaptation for post-copulatory female choice between rival ejaculates demands more research.

Analyses of between-sex differences have provided a powerful starting point for evolutionarily informed work on human sexuality. This early work set the stage for an evolutionary analysis of within-sex differences in human sexuality. A comprehensive theory of human sexual strategies must address both between-sex differences and within-sex differences in evolved psychology and manifest behavior.

Women with high sociosexual orientation inventory (SOI) scores may trade signs of willingness to invest for signs of ability to invest, instead of, or in addition to, genetic benefits. The target person's status traits affect women's judgments of sexual/physical attractiveness more than men's. An objective measure of a physical trait such as FA is therefore crucial in untangling the factors affecting women's judgments of attractiveness.

Gangestad & Simpson make a convincing case for male and female psychological access to sexual strategies that dispose us towards both faithful long-term mating and promiscuity – according to socio- ecological conditions. However, their model fails to acknowledge how the human self-system's mediation of conduct can permit us to override voluntarily the pseudo-imperatives of optimizing inclusive fitness.

Not all of the studies cited in the target article as evidence that fluctuating asymmetry (FA) predicts male mating success demonstrate that the observed asymmetry is, in fact, FA. FA is a population-level pattern of differences between sides. Unless the population-level distributional criteria of bilateral traits are reported, the meaning of asymmetry in individuals is unknown.

This response reinforces several major themes in our target article: (a) the importance of sex-specific, within-sex variation in mating tactics; (b) the relevance of optimality thinking to understanding that variation; (c) the significance of special design for reconstructing evolutionary history; (d) the replicated findings that women's mating preferences vary across their menstrual cycle in ways revealing special design; and (e) the importance of applying market phenomena to understand the complex dynamics of mating. We also elaborate on three points: (1) Men who have indicators of genetic fitness may provide more direct benefits when female demand for extra-pair and short-term sex is very low; (2) both men and women track ecological cues to make mating decisions; and (3) more research on female orgasm is needed.