Evidence for a Collective Intelligence Factor in the Performance of Human Groups
Psychologists have repeatedly shown that a single statistical factor—often called “general intelligence”—emerges from the correlations among people’s performance on a wide variety of cognitive tasks. But no one has systematically examined whether a similar kind of “collective intelligence” exists for groups of people. In two studies with 699 people, working in groups of two to five, we find converging evidence of a general collective intelligence factor that explains a group’s performance on a wide variety of tasks. This “c factor” is not strongly correlated with the average or maximum individual intelligence of group members but is correlated with the average social sensitivity of group members, the equality in distribution of conversational turn-taking, and the proportion of females in the group.
[Note: I find their use of a 10 minute Raven's Advanced Progressive Matrices (RAPM) to measure individual intelligence a bit problematic. The correlation of 10 minute RAPM with full RAPM is probably not that high (say, < .7). So they only have a noisy measure of individual intelligence. I didn't see that they took this uncertainty into account in a sophisticated way when analyzing the relation between c and avg or max IQ. This information is in the supplement.]
These results remind me (perhaps tangentially) of remarks by W.D. Hamilton in his paper Innate Social Aptitudes of Man:
The incursions of barbaric pastoralists seem to do civilizations less harm in the long run than one might expect. Indeed, two dark ages and renaissances in Europe suggest a recurring pattern in which a renaissance follows an incursion by about 800 years. It may even be suggested that certain genes or traditions of pastoralists revitalize the conquered people with an ingredient of progress which tends to die out in a large panmictic population for the reasons already discussed. I have in mind altruism itself, or the part of the altruism which is perhaps better described as self-sacrificial daring. By the time of the renaissance it may be that the mixing of genes and cultures (or of cultures alone if these are the only vehicles, which I doubt) has continued long enough to bring the old mercantile thoughtfulness and the infused daring into conjunction in a few individuals who then find courage for all kinds of inventive innovation against the resistance of established thought and practice. Often, however, the cost in fitness of such altruism and sublimated pugnacity to the individuals concerned is by no means metaphorical, and the benefits to fitness, such as they are, go to a mass of individuals whose genetic correlation with the innovator must be slight indeed. Thus civilization probably slowly reduces its altruism of all kinds, including the kinds needed for cultural creativity (see also Eshel 1972).
This paper by Hamilton is also of interest because of the nice discussion of multi-level selection (what is the proper unit of selection in evolutionary biology: the gene, the individual, the group... ?), a subject of recent controversy. In physics we would call this "effective field theory" or "relevant degrees of freedom" :-) That one might specialize to the appropriate unit of selection in a given context is equivalent to noting that we need not consider quarks or quantum mechanics to analyze the aerodynamics of a 747. In some contexts (e.g., turbulence or strongly coupled systems), interactions on many scales are relevant and the corresponding dynamics very complex. The same may be true for human evolution: genes, individuals and groups, even cultures, all interact nontrivially.