Moving beyond a focus on the individual to think seriously about group-level processes is relevant not just for cultural evolution but for human evolution overall. We are at a point in our understandings of evolutionary and behavioral processes that suggests we move beyond the reliance on a focus on individuals, single events, and single traits to a systems approach, including group dynamics, structure, and emergent traits, in analyses of evolutionary histories and processes (Bateson & Gluckman Reference Bateson and Gluckman2011; Hinde Reference Hinde1976a; Laland et al. Reference Laland, Odling-Smee and Feldman2000; Oyama et al. Reference Oyama, Griffiths and Gray2003; Sterelny Reference Sterelny2012).

Incorporating niche construction and social, behavioral, and symbolic inheritance, in addition to ecological and genetic inheritances, should be central in our examinations of human evolutionary trajectories and processes (e.g., Dunbar et al. Reference Dunbar, Gamble and Gowlett2010; Fuentes Reference Fuentes and Fry2013; Flynn et al. Reference Flynn, Laland, Kendal and Kendal2013; Henrich Reference Henrich2011; Jablonka & Lamb Reference Jablonka and Lamb2005). An explicit role for emergent group-level traits, social role diversification, and coordination makes good sense.

Smaldino argues that human groups produce emergent group-level traits that result in between-group differences in fitness and are heritable. If this is the case, then we need not only to describe such patterns in modern humans, but also to develop a model where these patterns (and the capacities for them) could have evolved. A core for such a model lies in the recognition that increasingly dense conception and transmission of information alongside substantive neurological and behavioral plasticity characterize “the human socio-cognitive niche” (Whiten & Erdal Reference Whiten and Erdal2012) and that humans use a hybrid learning system where central social and material skills are acquired by combining information from the social world and the physical-biological world (Sterelny Reference Sterelny2012). In short, modern human cooperation, collaboration, and coordination are related to organizational differentiation and to the semiotically and semantically rich human communication system, which evolved over the Pleistocene from simpler systems that had the potential to generate increased complexity. A full understanding of the role of group-level emergent traits requires a systemic explanation that is applicable (at least in part) across different members of our direct lineage over the past one to two million years.

In particular we need an explanation that has an explicit connection to the evolution of the genus Homo and its history of a “positive feedback loop that drove life history evolution and contributed to cultural change” (Anton & Snodgrass Reference Anton and Snodgrass2012, p. S492). This feedback system was an iterative process where increasing brain size, dietary quality, and cooperative behavior results in lowered extrinsic mortality risk, changes in cognition, body composition, life history parameters, and behavioral and communicative complexity (culture) (Anton & Snodgrass Reference Anton and Snodgrass2012; Sterelny Reference Sterelny2012). We need to move toward an integrative model that encompasses positive feedback systems at individual, subgroup and larger group levels, demographic processes, and local ecologies (Fuentes Reference Fuentes and Fry2013; in press). Smaldino's emphasis on development through overlapping cycles is a step in the right direction.

There is substantial evidence that behavioral and cultural inheritances play especially salient roles in evolutionary patterns and outcomes for the genus Homo, even before the emergence of fully modern Homo sapiens sapiens (Gamble et al. Reference Gamble, Gowlett and Dunbar2011; Henrich Reference Henrich2011; Kendal Reference Kendal2012; Richerson & Boyd Reference Richerson and Boyd2005). It was within the context of local and regional communities (comparable to the larger end of Smaldino's trait groups) that members of the genus Homo interfaced, interacted with, modified, and were modified by, social and ecological worlds during the course of our evolution (Fuentes, in press; Sterelny Reference Sterelny2012). I suggest that a focus on evolutionary processes at multiple levels (individual, subgroup, and community) and the feedback and interfaces between these levels, across the Pleistocene, can facilitate a linkage between Smaldino's model of the centrality of emergent group-level traits in modern humans and the systems of evolutionary processes in earlier members of the genus.

Unfortunately, Smaldino's reliance on battlefield, corporate, and sports analogies as metaphors of choice and on inter-group competition as a central driving factor in the evolutionary processes obfuscates the development of such attempts. Direct conflict, business, and sports and military models are not the only, or the best, heuristic tools for thinking about evolutionary processes, especially over the majority of human evolutionary history. Using this format, even metaphorically, limits the explanatory toolkit and constrains perspectives in modeling dynamic histories. It also discounts, or overlooks, possibilities that drift, and evolutionary processes aside from selection may play substantive roles in shaping trajectories. Smaldino also assumes a kind of consistent selective progress wherein as cultural knowledge and behaviors move across time, better ideas and practices replace those that are less effective. Such an assumption of clear directional progress is not warranted in a larger view of human evolution. Much of our history as a genus is better seen as ebb and flow of innovation and extinction, of progress and retrogress, in technologies, behavior, and adaptation.

While I applaud expanding the focus of evolutionarily relevant actions beyond the individual, Smaldino's definition of a trait group as a collection of individuals interacting to produce a trait and the assertion that such a group may range from a simple dyad to a population of thousands is problematic. I agree that both dyadic and the large-scale interactions can be evolutionarily relevant, but I do not think these two things can be assumed to be functionally equivalent entities in an evolutionary model.

Finally, and importantly, Smaldino assumes that once cooperation has evolved, the persistent association, interdependence, and information transmission between individuals enable the evolution of increased complexity in collaboration, the differentiation of roles, and a more structured social organization. I agree and suggest that a high level of cooperation shows up relatively early and forcefully in human (even hominin) evolution (Fuentes Reference Fuentes and Fry2013; Malone et al. Reference Malone, Fuentes and White2012). Thus, our explanations for much of the current hypercomplex behavior and cultural processes in modern humans need not include explanations for the extant baseline of cooperation; rather they, as Smaldino does, need to take it as a jumping off point and strive to explain not the baseline but the changes, and potential emergent properties, that it facilitates.