Reintroducing group selection to the human behavioral sciences

Abstract

In both biology and the human sciences, social groups are sometimes treated as adaptive units whose organization cannot be reduced to individual interactions. This group-level view is opposed by a more individualistic one that treats social organization as a byproduct of self-interest. According to biologists, group-level adaptations can evolve only by a process of natural selection at the group level. Most biologists rejected group selection as an important evolutionary force during the 1960s and 1970s but a positive literature began to grow during the 1970s and is rapidly expanding today. We review this recent literature and its implications for human evolutionary biology. We show that the rejection of group selection was based on a misplaced emphasis on genes as “replicators” which is in fact irrelevant to the question of whether groups can be like individuals in their functional organization. The fundamental question is whether social groups and other higher-level entities can be “vehicles” of selection. When this elementary fact is recognized, group selection emerges as an important force in nature and what seem to be competing theories, such as kin selection and reciprocity, reappear as special cases of group selection. The result is a unified theory of natural selection that operates on a nested hierarchy of units.The vehicle-based theory makes it clear that group selection is an important force to consider in human evolution. Humans can facultatively span the full range from self-interested individuals to “organs” of group-level “organisms.” Human behavior not only reflects the balance between levels of selection but it can also alter the balance through the construction of social structures that have the effect of reducing fitness differences within groups, concentrating natural selection (and functional organization) at the group level. These social structures and the cognitive abilities that produce them allow group selection to be important even among large groups of unrelated individuals.

Towards a unified science of cultural evolution

“…Hence, biologists frequently model natural selection acting not only on the individual (Darwin 1859(Darwin /1968, but at any level that exhibits variation, differential fitness, and inheritance of fitness-related characters (Lewontin 1970). This may include levels below the individual, such as the case of selfish DNA (Orgel & Crick 1980) which is selected within the genome but which does not directly affect selection at the phenotypic level, or above the individual, as in the case of group selection (Sober & Wilson 1998;Wilson & Sober 1994), species selection (Stanley 1975), or clade selection (Vermeij 1996). We see no difficulty envisaging similar multilevel selection occurring in cultural evolution, negating much of Read's criticism that Darwinian evolution cannot deal with selection operating at the social level, as with kin terminology ("The selection acting on kinship terminologies occurs at the level of structural properties").…”

A phylogenetic approach to cultural evolution

“…Survivors, especially reproductive-age women, might integrate themselves into the victorious cultures, thus cultural extinction does not necessarily imply genetic extinction; but such migrants would have to learn the ways of their new community if they are to survive and reproduce among them. Several authors have argued that such population dynamics can lead to group-level selection occurring in human cultural evolution [6,[13][14][15] and could explain a range of uniquely human behaviours, from high-level cooperation with unrelated individuals [8,14,16] to ethnic markers and psychology [17]. Such processes could maintain the identity of discrete cultural groups even when genetic distinctions are more blurred or even absent.…”

The Robust Beauty of Majority Rules in Group Decisions.

“…The majority rule has many virtues: It is "transparent" and the easiest of all social decision rules to execute; it is based on a simple principle of equal participation and equal power; it encourages the expression of sincere personal beliefs, rather than conformity; and it yields more effective problem solutions than typical (and sometimes even most accurate) members could achieve. The present article is an exploration of the capacity of the majority rule and the closely related plurality rule to produce accurate judgments.The majority rule is popular across the full spectrum of human groups from hunter-gatherer tribal societies (Boehm, 1996;Boyd & Richerson, 1985;Wilson, 1994) to modern industrial democracies (Mueller, 1989). Certainly, in ad hoc Western groups, it seems to be the decision rule most frequently adopted to make formal social choices in popular elections, legislatures, and committees.…”