Dog lovers can gloat...

A new paper in the Proceedings of the National Academy of Sciences, (S. Shultz, R. Dunbar, 2010) appears to demonstrate something that has long been suspected. The debate about the evolution of brain size, and thus intelligence and consciousness has been over the question of whether or not encephalization was universal (that is to say most lineages exhibited it) or whether the evolution of brain size affected groups differently and was correlated with certain biological and ecological factors. What Shultz and Dunbar demonstrat in their paper is that highly social species tend to have larger brains than solitary species.

This isn't entirely earth shattering of course. Because on one level it has been rather obvious that evolutionary encephalization (increases in brain size relative to body mass) hasn't been exactly uniform across the mammals. Predators have larger brains than their prey. Social species tend to have larger brains than non-social species. Omnivores tend to have larger brains than specialists. However researchers have, up to this point, drawn their conclusions by comparing extant species. What is unique about the current research is that it examines encephalization within evolutionary lineages rather than between extant species.

Click on the link to read the Sciencenet Daily summary. Also you can, and should read the abstract.