Social tinkering focuses on how the interactions of multiple individuals who participate in joint activities with shared goals within a group can contribute to cultural evolution through myopic (i.e., of the moment) directed and innovative solutions to local coordination problems in situ. The focus on directed innovation and interaction is a clear advance over existing accounts of cultural evolution, as this process is often underappreciated in the existing cultural evolution literature. However, the social tinkering account does not sufficiently consider the role of competition and selection (both between and within groups). In addition, it underplays the diversity of culturally evolved niches (e.g., Kashima, Bain, & Perfors, Reference Kashima, Bain and Perfors2019; Laland, Odling-Smee, & Feldman, Reference Laland, Odling-Smee and Feldman2000). These are not trivial issues: they have important implications for understanding cultural complexity and cultural change.

Social tinkering highlights the coordination problem that occurs when individuals participate in a joint activity – that is, once the tinkerers in a group have already largely agreed on their shared goals. While this is an important stage in cultural evolution, it bypasses the fundamental evolutionary problem of cooperation: how the tinkerers come to share goals and participate in the joint activity to begin with. The emergence of cooperation is a long-standing puzzle in the study of cultural evolution (e.g., Axelrod & Hamilton, Reference Axelrod and Hamilton1981; Henrich & Henrich, Reference Henrich and Henrich2006; Nowak, Reference Nowak2006). Given that human behaviors are expected to adapt to the local environment (e.g., Anderson, Reference Anderson1990; Lieder & Griffiths, Reference Lieder and Griffiths2020), different individuals and subgroups that have adapted to different local environments in the past can have divergent goals and strategies for goal attainment. These diverse individuals and subgroups may perceive new local challenges differently, form different problem representations, and propose different solutions to the challenges.

This is important because without a shared goal, the diversity of directed innovations that solve local challenges may be highly diverse across interaction situations and people. As a result, the innovations may look more like random variation in the aggregate; at the very least, any level of analysis that presumes that goals are shared and homogenous will miss important parts of the puzzle. For example, different people might approach resource sharing with diverse goals, such as maximizing their gain, reducing others’ shares, sharing it equally, striving for equity, etc. Moreover, those goals might change across interactions or in response to changes in social context (e.g., the existence of drought, the presence of trustworthy institutions that can allocate food).

A theoretical framework focusing solely on directed innovation without paying heed to individual and situational variations in goals to be pursued in joint activities within the population would miss the psychological micro-dynamics of cultural evolution. In other words, without also theorizing about or considering diverse goals and circumstances across individuals, social tinkering alone will fail to realize the potential outlined in the target article. The account additionally requires an explanation of selection: when diverse goals are available, which goals tend to get selected for a joint activity and why?

The problem goes deeper. Even when there is a shared goal, cooperation often comes at a cost, which can preclude social alignment. Cooperation can create an opportunity cost: focusing on one goal may take resources away from another goal that some individuals may value more. Moreover, for many coordinated solutions, individuals need to abide by the conventional solution in order to reap the benefits. For example, the express lane at the supermarket speeds checkout times for everyone as long as item limits are respected, but not if they aren’t. While these solutions can tolerate some deviations, if there is too much violation, any benefit from the coordinated solution is lost. In order to manage this, groups may be willing to bear the costs of institutions that ensure that individuals abide by the rules (e.g., Gurerk, Irlenbusch, & Rockenbach, Reference Gurerk, Irlenbusch and Rockenbach2006). The groups that are better at managing these costs and enforcing cooperation may then thrive relative to groups that do not. In other words, competition between groups (or group selection) cannot be ignored.

Competition and selection can play out within groups too. Imagine that two equal-payoff solutions to the same coordination problem are simultaneously proposed in recurrent joint activities (e.g., walk on the left or the right side of the pavement). In that situation, one solution needs to be ultimately selected as legitimate. This selection process often involves much more than negotiation between equal status/power tinkerers. While both solutions are instances of directed innovation, settling on a single convention may involve competitive selection, via competition between individuals or subgroups with unequal power within the group. A privileged subgroup can exert a strong selection pressure against the solutions of the less privileged, regardless of the fitness of a solution to the momentary local challenge (Fracchia & Lewontin, Reference Fracchia and Lewontin1999; Richerson et al., Reference Richerson, Baldini, Bell, Demps, Frost, Hillis, Mathew, Newton, Naar, Newson, Ross, Smaldino, Waring and Zefferman2016). If a power imbalance is randomly distributed, it may not affect the trajectory of cultural evolution in the long run. However, if power or status imbalances are structured, widespread, and stable over generations – as they often are – the effect of these imbalances may accumulate across generations and shape cultural evolution in a way that social tinkering theory as currently formulated cannot capture.

Taken together, competition within and/or between groups to select coordinated solutions facilitates cultural niche construction, where groups change the socio-ecological environment, which in turn ends up structuring their evolution (Kashima et al., Reference Kashima, Bain and Perfors2019; Laland et al., Reference Laland, Odling-Smee and Feldman2000). While the current proposal nods to the roles of competition and adversarial interaction, elaboration is needed on (a) the potential for goal selection to create a cultural niche with structural power imbalance and (b) how the maintenance of group identity/goals can work to the detriment of functional adaptiveness.

In summary, although the social tinkering account is a valuable addition to the literature, it needs to more fully address how diverse groups emerge and interact. A good starting point is to critically evaluate who gets to participate in social tinkering, especially as the costs of cooperative selection and the complexity of cultural systems scale up.