Speaker series
Evolution and the Social Mind
Narrative resources
 
Group selection, selection in social contexts,
and levels of selection
 
An Open Discussion
Department of Anthropology, UCSB
May 8, 1998 from 12:30pm to 2pm
Humanities and Social Sciences Building 2001A
 
 
Discussion Theme
 
This week will not involve an outside speaker, but will instead be a general discussion of a topic that many regular participants have asked be explored in an open forum.  The topic will be explored with a series of questions, including what the relative rates of evolution at different levels of selection, how to test for evidence of complex adaptations produced by selection at different levels of selection, and possible instances of group selection from parasitic infections in hosts, to warrior castes in eusocial insect species whose queens engage in multiple matings, to D.S. Wilson's reanalyses of reciprocity and kin selection as instances of group selection, to putatitive human cases.

For background, attendees are encouraged to consult George William's Adaptation and Natural Selection, and for a more recent and opposed view, David Sloan Wilson's and Eliot Sober's paper in Behavioral and Brain Sciences, "Re-Introducing Group Selection To The Human Behavioral
Sciences" (the on-line version is without the commentary).
 

 
Wilson & Sober 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 view 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. During the 1960's and 70's most biologists rejected group selection as an important evolutionary force but a positive literature began to grow during the 70's 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 ostensible alternatives, 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. "
 

 

Speaker series
Evolution and the Social Mind
Narrative resources