Most of the major breakthroughs in the history of science occurred not exclusively through pure benchmark research but by the development and application of new theoretical paradigms, which, by challenging long-standing assumptions, completely reformulated the foundational pillars of academic disciplines, providing a new framework through which the experimental data could be understood with basis on a different heuristic perspective. Illustrative examples of such phenomena were the revolution of relativistic mechanics in the early 20^th century, which shake the millennial human confidence in the absoluteness of time (Spector Reference Spector1972), and the emergence of quantum physics, which, by bringing completely new (and sometimes unusual) concepts, such as the wave-particle duality, the discreteness/noncontinuous quality of energy, and the uncertainty principle, challenged some of the most primitive certainties of the human mind regarding the basic nature of the physical world (Greenberger et al. Reference Greenberger, Reiter and Zeilinger1999).

In his target article, Smaldino defends a new paradigm of cultural evolution based not on the individuals' characteristics, but rather on more global collective properties described as “group-traits,” which emerge when a group of individuals exhibit both differentiation and organization. By providing a broader perspective on the effects of inter-individual interactions in terms of the emergence of new qualities at the group level, the proposed analysis would more powerfully explain the evolution of cultural traits than previous attempts focused exclusively on the properties of the interacting individuals. Besides its more immediate implications to the field of social and evolutionary psychology, such new epistemological approach, as a paradigm that shifts the focus from the individual to the group level as the basic unit involved in the dynamics of cultural evolution, promises to have a major impact over other frontline research areas that, up to now, have operated essentially with basis on the characteristics of few interacting individuals.

For example, although neuroeconomics has emerged as a new research field in which the concepts of economics and probability theory have been used to investigate human decision making under risk and uncertainty (Loewenstein et al. Reference Loewenstein, Rick and Cohen2008), the vast majority of previous studies in this field have been focused on individual choices and personal intertemporal preferences (Kalenscher et al. Reference Kalenscher, Tobler, Huijbers, Daselaar and Pennartz2010; MacKillop et al. Reference MacKillop, Amlung, Wier, David, Ray, Bickel and Sweet2012) The incorporation of the new concepts developed in the target article, such as collaborative interdependence (instead of cooperation) and levels of selection, may contribute to the enrichment of current investigational protocols, paving the way for the emergence of a macro-neuroeconomics of group decision making and collective behavior. Such a new research field would not only enhance our understanding about the neural basis of the psychological features that are believed to be strongly influenced by social constraints (Mojzisch & Krug Reference Mojzisch and Krug2008; Sanfey Reference Sanfey2007), such as religious and political preferences (both of which have received little attention by past neuroeconomics studies), but would also provide new insights regarding the social evolutionary mechanisms that may cause social virtues (like empathy, altruism, wisdom, social responsibility, and patriotism) (Güroğlu et al. Reference Güroğlu, van den Bos and Crone2009; Meeks & Jeste Reference Meeks and Jeste2009) to produce long-term collective effects that transcends their immediate impact in terms of individual inclusive fitness (Moreira et al. Reference Moreira, Pacheco and Santos2013).

Similarly, although game theory has flourished in the twentieth century as a new set of powerful research methods dedicated to the analysis of the dynamics of personal choices, mutual cooperation, and conflict under different environmental setups (von Neumann & Morgenstern Reference von Neumann and Morgenstern1946), up to now very few game theory studies have employed paradigms that go beyond the level of interaction between few individuals or social entities. In fact, although the effect of natural selection as emerging from repeated interactions between individuals have been incorporated to the general framework of such investigations, giving birth to a new discipline called evolutionary game theory (Maynard Smith Reference Maynard Smith1982), the vast majority of studies in this field have been devoted to the analysis of population dynamics of biological ecosystems (Hofbauer & Sigmund Reference Hofbauer and Sigmund1998; Zeeman Reference Zeeman1980). In a critical analysis, the major obstacle to extending game theory methodology to more complex social situations is that, unlike the simple interactions observed in natural systems (such as the predator-prey or host-parasite relations), human social systems involve a much more complex network of hierarchical social structures interacting through heterogeneous, interdependent, and dynamic relationships that often challenge the ability of mathematical modeling.

Additionally, the unique capacity of human beings of predicting other individuals' behavior with basis on common knowledge assumptions (the so-called theory of mind) (Saxe & Kanwisher Reference Saxe and Kanwisher2003), as well as to rationally analyze the dynamics of their surrounding environment and to adapt their personal behavior accordingly, poses another level of complexity in which not only actual facts, but also the subjective perception of such facts plays a decisive role in final decisions and observed collective behavior. These are some of the reasons why previous experimental research in behavioral and social sciences have yielded results that are very different than those predicted by standard models of game theory involving players who employ strict instrumental rationality to maximize their expected utility (Colman Reference Colman2003; Gopher et al. Reference Gopher, Itkin-Webman, Erev, Meyer and Armony2000).

In this context some important aspects highlighted by Smaldino regarding the emergence, maintenance, and adaptiveness of group-level traits (such as the key role of labor division, leaders and religion, the importance of repeated assemblies, and the influence of technology) may provide the basic elements for construction of more complex models of social interaction. It is important to emphasize that such type of theoretical research have not only important consequences for future academic investigations, but also very practical implications, as exemplified by the emergence of applied disciplines with major social applications such as neuromarketing (Fisher et al. Reference Fisher, Chin and Klitzman2010) and neurolaw (Meynen Reference Meynen2013).

In summary, although the main point defended in the target article was the adoption of group-level traits in the analysis of cultural evolution, the complex theoretical pathway through which Smaldino struggled to safeguard his thesis constitutes a legacy of new conceptual developments that is expected to strongly influence the future of basic science and applied research in several different fields. As Ernest Hemingway said: