The target article by Ko and Neuberg is an initial, promising attempt to integrate the theory of “affordance management” (Neuberg et al. Reference Neuberg, Kenrick, Schaller, Fiske, Gilbert and Lindzey2010) with a life history perspective on how fitness-relevant goals change across life stages. A coherent evolutionary reframing of the Gibsonian concept of affordances is overdue, and was foreshadowed decades ago by Miller and Todd (Reference Miller, Todd, Banzhaf and Eeckman1995) (see Miller (Reference Miller2007) for a detailed, highly relevant treatment of “fitness affordances” and their role in evolutionary psychology). In this commentary, I leave aside the specific predictions made in the target article to concentrate on the underlying model of life stages, which – by the authors’ own admission – is still relatively crude and underdeveloped. I argue that accurately tracking the emergence, use, and transformation of affordances across the life course will require a sophisticated, fine-grained model that combines ultimate considerations of adaptive function with a proximate understanding of the processes involved.

Ko and Neuberg provisionally consider three major life stages labeled as “childhood,” “mating,” and “parenting.” This segmentation raises a number of problems, starting with the implicit tension between two alternative definitions of stages – one based on developmental patterns (as in “childhood” or “adolescence”) and one based on goal priorities (as in “mating” or “parenting”). To follow a consistent approach, one might recast childhood as the “growth” stage; however, childhood is about much more than just growth, and the same applies to most other life stages, which are characterized by profiles of goals and motivations rather than a single overarching priority. The authors recognize this when they allow for overlap between stages, but the solution is not very satisfying. An even bigger problem is that the adaptive goals considered by the authors do not map neatly on their subdivision: notably, the first manifestations of mating competition and (proto)sexual/romantic attraction do not usually emerge with puberty, but during middle childhood (approximately 6–11 years of age; see Herdt & McClintock, Reference Herdt and McClintock2000; Del Giudice, Reference Del Giudice2014). In fact, the force of sexual selection has likely contributed to shaping the developmental features of this stage (corresponding to juvenility in primates and other social mammals), with implications for the emergence and intensification of sex differences in muscularity, aggression, and even attachment styles (Del Giudice, Reference Del Giudice2014, Reference Del Giudice2015; Del Giudice et al., Reference Del Giudice, Angeleri and Manera2009). The temporal decoupling between different steps in the expression of mating motivations is likely made possible by the physiological splitting of human puberty into adrenarche (the gradual awakening of the adrenal glands that marks the transition to middle childhood) and gonadarche (the awakening of the gonads that marks the beginning of adolescence). Crucially, some important affordances related to mating (including the sex ratio, the intensity of status/dominance competition, and the attractiveness/mate value of both oneself and potential partners) seem to become salient and consequential already in middle childhood, well before the completion of bodily growth and the onset of sexual maturation.

A related difficulty with defining life stages based on adaptive goals is that developmental plasticity (in the form of predictive-adaptive responses, developmental “calibration” etc.) is inherently forward-looking, so that cues received in one life stage may influence the phenotype expressed at a later stage. For example, certain affordances that were salient in early “childhood” may entrain developmental processes that shape the later expression of “mating” or even “parenting.” Of course, this is only a problem if one implicitly assumes (as is often done in the Gibsonian tradition) that affordances must reflect the organism’s current goals and concerns; but nothing prevents an organism from experiencing affordances in view of potential future goals (e.g., I can notice a tree full of delicious ripe fruits, and memorize where it is even if I’m not hungry at the moment). Equating life stages with particular goals invites this type of confusion; instead, one should recognize that adaptive goals and motivations often follow complex, indirect, and multi-step trajectories throughout the life course.

Decades of research in evolutionary anthropology have yielded a detailed model of the stages of the human life course and the corresponding transitions (e.g., Bogin, Reference Bogin1999). A reasonably fine-grained taxonomy could include the following: a prenatal stage (rich in potential affordances: see e.g., Brown et al. (Reference Brown, Gettler and Rosenbaum2024); Ellison (Reference Ellison2010)); birth; infancy; early childhood; the “juvenile transition” (Del Giudice et al., Reference Del Giudice, Angeleri and Manera2009); middle childhood; adolescence; adulthood; and (in women) menopause and the post-menopause. These obligate stages and transitions are complemented by facultative phases, including pregnancy, parenthood (which may be further segmented according to the offspring’s life stages), and grandparenthood. Given the universality of marriage across human cultures (Brown, Reference Brown1991; Chapais, Reference Chapais2009), being in a committed, socially sanctioned “marriage-like” relationship may qualify as an evolved facultative phase sustained by specific adaptations. To identify states such as marriage and parenthood, I suggest using the label of life “phases” instead of “stages” because (a) they do not follow a strict sequence; (b) they can co-occur with one another and with more than one life stage; and (c) unlike obligate stages, they are reversible (e.g., marriage may end with divorce or with the death of the spouse; parenthood may end with the death of the child) and can be experienced more than once. The distinction between obligate life stages and facultative life phases helps describe a number of important patterns, with more precision than would be permitted by a generic notion of “overlap.” This taxonomy, or something like it, could be integrated into future revisions of the affordance management framework.

A granular taxonomy of life stages, phases, and transitions, each with a characteristic (and possibly sex-differentiated) profile of goals and priorities, would also help extend the range of affordances covered by the framework to those relevant to various kinds of dangers and protections, the acquisition of material and informational resources, the formation of groups and alliances, and so forth. Indeed, a sophisticated model of life stages calls for an equally sophisticated model of motivation (see Del Giudice, Reference Del Giudice, Al-Shawaf and Shackelford2024, 2023, for some building blocks); and a lifespan theory of affordances like the one presented in the target article needs both, if it is going to succeed in its ambitious goals.