Multilevel cultural evolution: From new theory to practical applications.

Evolutionary science has led to many practical applications of genetic evolution but few practical uses of cultural evolution. This is because the entire study of evolution was gene centric for most of the 20th century, relegating the study and application of human cultural change to other disciplines. The formal study of human cultural evolution began in the 1970s and has matured to the point of deriving practical applications. We provide an overview of these developments and examples for the topic areas of complex systems science and engineering, economics and business, mental health and well-being, and global change efforts.

Groups as organisms: Implications for therapy and training.

The intellectual tradition of individualism treats the individual person as the fundamental unit of analysis and reduces all things social to the motives and actions of individuals. Most methods in clinical psychology are influenced by individualism and therefore treat the individual as the primary object of therapy/training, even when recognizing the importance of nurturing social relationships for individual wellbeing. Multilevel selection theory offers an alternative to individualism in which individuals become part of something larger than themselves that qualifies as an organism in its own right. Seeing individuals as parts of social organisms provides a new perspective with numerous implications for improving wellbeing at all scales, from individuals to the planet.

The pandemic exposes human nature: 10 evolutionary insights.

Humans and viruses have been coevolving for millennia. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the virus that causes COVID-19) has been particularly successful in evading our evolved defenses. The outcome has been tragic-across the globe, millions have been sickened and hundreds of thousands have died. Moreover, the quarantine has radically changed the structure of our lives, with devastating social and economic consequences that are likely to unfold for years. An evolutionary perspective can help us understand the progression and consequences of the pandemic. Here, a diverse group of scientists, with expertise from evolutionary medicine to cultural evolution, provide insights about the pandemic and its aftermath. At the most granular level, we consider how viruses might affect social behavior, and how quarantine, ironically, could make us susceptible to other maladies, due to a lack of microbial exposure. At the psychological level, we describe the ways in which the pandemic can affect mating behavior, cooperation (or the lack thereof), and gender norms, and how we can use disgust to better activate native "behavioral immunity" to combat disease spread. At the cultural level, we describe shifting cultural norms and how we might harness them to better combat disease and the negative social consequences of the pandemic. These insights can be used to craft solutions to problems produced by the pandemic and to lay the groundwork for a scientific agenda to capture and understand what has become, in effect, a worldwide social experiment.

Clinical psychology is an applied evolutionary science.

Historically there has been only a limited relationship between clinical psychology and evolutionary science. This article considers the status of that relationship in light of a modern multi-dimensional and multi-level extended evolutionary approach. Evolution can be purposive and even conscious, and evolutionary principles can give guidance and provide consilience to clinical psychology, especially as it focuses more on processes of change. The time seems ripe to view clinical psychology as an applied evolutionary science.

Core design principles for nurturing organization-level selection.

Dynamic relationships between individuals and groups have been a focus for evolutionary theorists and modelers for decades. Among evolutionists, selfish gene theory promotes reductionist approaches while multilevel selection theory encourages a context-sensitive approach that appreciates that individuals and groups can both matter. Among economists, a comparable contrast is found wherein the reductionist shareholder primacy theory most associated with Nobel laureate Milton Friedman is very different from the context-sensitive focus on managing common resources that Nobel laureate Elinor Ostrom pioneered. In this article, we examine whether the core design principles that Ostrom advanced can cultivate selection at supra-individual levels across different domains. We show that Ostrom's design principles that were forged in the context of managing natural resources are associated with positive outcomes for human social groups across a variety of functional domains.

Laying the foundation for evonomics.

The target article is a major step toward integrating the biological and human-related sciences. It is highly relevant to economics and public policy formulation in the real world, in addition to its basic scientific import. My commentary covers a number of points, including avoiding an excessively narrow focus on agriculture, the importance of multilevel selection and complex systems theory, and utopic versus dystopic scenarios for the future.

Intentional cultural change.

As a process of blind variation and selective retention, evolution lacks intentionality. Nevertheless, intentional processes can be a product of evolution and can double back to effect evolution. This article briefly describes how intentional processes evolve, how they figure in human cultural evolution, and how future cultural evolution needs to become more intentional.

Groups as units of functional analysis, individuals as proximate mechanisms.

Whenever selection operates at a given level of a multitier hierarchy, units at that level should become the object of functional analysis, and units at lower levels should be studied as proximate mechanisms. This intuition already exists for the study of genes in individuals, when individuals are the unit of selection. It is only beginning to be applied for the study of individuals in groups, when groups are the unit of selection. Smaldino's target article is an important step in this direction with an emphasis on human cultural evolution, but the same algorithm applies to all multilevel evolutionary processes.

Evolving the future: toward a science of intentional change.

Humans possess great capacity for behavioral and cultural change, but our ability to manage change is still limited. This article has two major objectives: first, to sketch a basic science of intentional change centered on evolution; second, to provide examples of intentional behavioral and cultural change from the applied behavioral sciences, which are largely unknown to the basic sciences community. All species have evolved mechanisms of phenotypic plasticity that enable them to respond adaptively to their environments. Some mechanisms of phenotypic plasticity count as evolutionary processes in their own right. The human capacity for symbolic thought provides an inheritance system having the same kind of combinatorial diversity as does genetic recombination and antibody formation. Taking these propositions seriously allows an integration of major traditions within the basic behavioral sciences, such as behaviorism, social constructivism, social psychology, cognitive psychology, and evolutionary psychology, which are often isolated and even conceptualized as opposed to one another. The applied behavioral sciences include well-validated examples of successfully managing behavioral and cultural change at scales ranging from individuals to small groups to large populations. However, these examples are largely unknown beyond their disciplinary boundaries, for lack of a unifying theoretical framework. Viewed from an evolutionary perspective, they are examples of managing evolved mechanisms of phenotypic plasticity, including open-ended processes of variation and selection. Once the many branches of the basic and applied behavioral sciences become conceptually unified, we are closer to a science of intentional change than one might think.

Adaptive long-range migration promotes cooperation under tempting conditions.

Migration is a fundamental trait in humans and animals. Recent studies investigated the effect of migration on the evolution of cooperation, showing that contingent migration favors cooperation in spatial structures. In those studies, only local migration to immediate neighbors was considered, while long-range migration has not been considered yet, partly because the long-range migration has been generally regarded as harmful for cooperation as it would bring the population to a well-mixed state that favors defection. Here, we studied the effects of adaptive long-range migration on the evolution of cooperation through agent-based simulations of a spatial Prisoner's Dilemma game where individuals can jump to a farther site if they are surrounded by more defectors. Our results show that adaptive long-range migration strongly promotes cooperation, especially under conditions where the temptation to defect is considerably high. These findings demonstrate the significance of adaptive long-range migration for the evolution of cooperation.

The evolutionary basis of risky adolescent behavior: implications for science, policy, and practice.

This article proposes an evolutionary model of risky behavior in adolescence and contrasts it with the prevailing developmental psychopathology model. The evolutionary model contends that understanding the evolutionary functions of adolescence is critical to explaining why adolescents engage in risky behavior and that successful intervention depends on working with, instead of against, adolescent goals and motivations. The current article articulates 5 key evolutionary insights into risky adolescent behavior: (a) The adolescent transition is an inflection point in development of social status and reproductive trajectories; (b) interventions need to address the adaptive functions of risky and aggressive behaviors like bullying; (c) risky adolescent behavior adaptively calibrates over development to match both harsh and unpredictable environmental conditions; (d) understanding evolved sex differences is critical for understanding the psychology of risky behavior; and (e) mismatches between current and past environments can dysregulate adolescent behavior, as demonstrated by age-segregated social groupings. The evolutionary model has broad implications for designing interventions for high-risk youth and suggests new directions for research that have not been forthcoming from other perspectives.

Residential mobility and prosocial development within a single city.

Neighborhood social dynamics have been shown to impact behavioral development in residents, including levels of prosociality (i.e. positive social behavior). This study explores whether residential moves to neighborhoods with different social dynamics can influence further prosocial development. Prosociality, five domains of social support, and residential location were tracked between 2006 and 2009 in 397 adolescents across a small city in upstate New York. Analysis compared the role of the different forms of social support in prosocial development for movers versus non-movers. The effects of one's neighborhood of residence at Time 2 were also compared between movers and non-movers. Prosocial development in these two groups responded similarly to all forms of social support, including from neighbors. Movers experienced a greater increase in prosociality the more residentially stable the adolescent population of their new neighborhood of residence. Such neighborhood characteristics were not influential in the prosocial development of non-movers.

A program for at-risk high school students informed by evolutionary science.

Improving the academic performance of at-risk high school students has proven difficult, often calling for an extended day, extended school year, and other expensive measures. Here we report the results of a program for at-risk 9th and 10th graders in Binghamton, New York, called the Regents Academy that takes place during the normal school day and year. The design of the program is informed by the evolutionary dynamics of cooperation and learning, in general and for our species as a unique product of biocultural evolution. Not only did the Regents Academy students outperform their comparison group in a randomized control design, but they performed on a par with the average high school student in Binghamton on state-mandated exams. All students can benefit from the social environment provided for at-risk students at the Regents Academy, which is within the reach of most public school districts.

Eight criticisms not to make about group selection.

Group selection, which was once widely rejected as a significant evolutionary force, is now accepted by all who seriously study the subject. There is still widespread confusion about group selection, however, not only among students and the general public, but among professional evolutionists who do not directly study the subject. We list eight criticisms that are frequently invoked against group selection, which can be permanently laid to rest based upon current knowledge. Experts will always find something to critique about group selection, as for any important subject, but these eight criticisms are not among them. Laying them to rest will enable authors to openly use the term group selection without being handicapped during the review process.

Intrasexual peer aggression and dating behavior during adolescence: an evolutionary perspective.

It has been suggested that the use of intrasexual aggression is a form of competition associated with reproductive opportunities. Here the authors investigated the relationship between retrospective dating and flirting behavior and peer aggression and victimization during middle and high school. Results indicate that the use of peer aggression was associated with adaptive dating outcomes in both sexes, whereas experiencing peer victimization was correlated with maladaptive dating behaviors among females only. Females who perpetrated high levels of indirect (i.e. nonphysical) aggression reported that they began dating at earlier ages in comparison to their peers, whereas aggressive males reported having more total dating partners. Experiencing female-female peer victimization was correlated with a later onset of dating behavior, more total dating partners, and less male flirtation while growing up. This report strengthens the connection between adolescent peer aggression and reproductive competition, suggesting a potential functionality to adolescent peer aggression in enhancing one's own mating opportunities at the expense of rivals.

Community perception: the ability to assess the safety of unfamiliar neighborhoods and respond adaptively.

When entering an unfamiliar neighborhood, adaptive social decisions are dependent on an accurate assessment of the local safety. Studies of cities have shown that the maintenance of physical structures is correlated with the strength of ties between neighbors, which in turn is responsible for the crime level. Thus it should be theoretically possible to intuit neighborhood safety through the physical structures alone. Here we test whether people have this capacity for judging urban neighborhoods with 3 studies in which individuals observed photographs of unfamiliar neighborhoods in Binghamton, New York. Each study was facilitated by data collected during previous studies performed by the Binghamton Neighborhood Project studies. In the 1st study, observer ratings on neighborhood social quality agreed highly with reports by those living there. In the 2nd, a separate sample of participants played an economic game with adolescent residents from pictured neighborhoods. Players exhibited a lower level of trust toward adolescents from neighborhoods whose residents report lesser social quality. In the 3rd study, the maintenance of physical structures and the presence of businesses explained nearly all variation between neighborhoods in observer ratings (89%), whereas the specific features influencing play in Study 2 remained inconclusive. These and other results suggest that people use the general upkeep of physical structures when making wholesale judgments of neighborhoods, reflecting a adaptation for group living that has strong implications for the role of upkeep in urban environments.

Associations between dopamine D4 receptor gene variation with both infidelity and sexual promiscuity.

BACKGROUND: Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection), little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR) polymorphism in exon III of the human dopamine D4 receptor gene (DRD4) has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity. METHODOLOGY/PRINCIPAL FINDINGS: We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+) report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a "one-night stand") and report a more than 50% increase in instances of sexual infidelity. CONCLUSIONS/SIGNIFICANCE: DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism.

The role of multilevel selection in the evolution of sexual conflict in the water strider aquarius remigis.

In evolution, exploitative strategies often create a paradox in which the most successful individual strategy "within" the group is also the most detrimental strategy "for" the group, potentially resulting in extinction. With regard to sexual conflict, the overexploitation of females by harmful males can yield similar consequences. Despite these evolutionary implications, little research has addressed why sexual conflict does not ultimately drive populations to extinction. One possibility is that groups experiencing less sexual conflict are more productive than groups with greater conflict. However, most studies of sexual conflict are conducted in a single isolated group, disregarding the potential for selection among groups. We observed Aquarius remigis water striders in a naturalistic multigroup pool in which individuals could freely disperse among groups. The free movement of individuals generated variation in aggression and sex-ratio among groups, thereby increasing the importance of between-group selection compared to within-group selection. Females dispersed away from local aggression, creating more favorable mating environments for less-aggressive males. Furthermore, the use of contextual analysis revealed that individual male aggression positively predicted fitness whereas aggression at the group level negatively predicted fitness, empirically demonstrating the conflict between levels of selection acting on mating aggression.

Population structure influences sexual conflict in wild populations of water striders.

In sexual conflict, aggressive males frequently diminish the long-term reproductive success of females in efforts to gain a short-term advantage over rival males. This short-term advantage can selectively favour high-exploitation males. However, just as the over-exploitation of resources can lead to local extinction, the over-exploitation of females in the form of harassment by aggressive males can yield similar consequences resulting in reduced female fecundity, increased female mortality and overall decline in mating activity. This outcome may often be prevented by selection acting at multiple levels of biological organization. Directional selection favouring aggressive exploitation within groups can be balanced by directional selection amongst groups opposing exploitation. Such between-group selection has recently been demonstrated in laboratory studies of water striders, where the conditional dispersal of individuals increased variation amongst groups and influenced the balance of selection toward reduced male aggression. This multilevel selection (MLS) framework also provides predictive value when investigating natural populations differing in their relative strength of selection within versus among groups. For water striders, the consequences of local exploitation cause fitness differences between groups, favouring less aggressive males. Inconsistently flowing ephemeral streams consist of isolated pools that prevent aggressive male water striders from escaping the consequences of local exploitation. We, therefore, predicted that inconsistently flowing ephemeral streams would favour the evolution of less aggressive males than would perennial streams, which allow aggressive males to move more freely and to escape the group-level costs of their aggression. Comparing two neighbouring streams during the mating season, we found that males dispersed naturally between pools at much higher rates in the perennial stream than in the ephemeral stream. As predicted, we found that males from the perennial stream were significantly more aggressive than those from the ephemeral stream. We also found that dispersers were significantly more aggressive than non-dispersers within each stream. These field results illustrate the relevance of the MLS framework in our understanding of the evolution of sexual conflict.