Big brains, enhanced cognition, and response of birds to novel environments

Abstract

The widely held hypothesis that enlarged brains have evolved as an adaptation to cope with novel or altered environmental conditions lacks firm empirical support. Here, we test this hypothesis for a major animal group (birds) by examining whether largebrained species show higher survival than small-brained species when introduced to nonnative locations. Using a global database documenting the outcome of >600 introduction events, we confirm that avian species with larger brains, relative to their body mass, tend to be more successful at establishing themselves in novel environments. Moreover, we provide evidence that larger brains help birds respond to novel conditions by enhancing their innovation propensity rather than indirectly through noncognitive mechanisms. These findings provide strong evidence for the hypothesis that enlarged brains function, and hence may have evolved, to deal with changes in the environment. brain evolution ͉ phenotypic flexibility ͉ environmental change

The Expensive Brain: A framework for explaining evolutionary changes in brain size

“…While there is no doubt that larger brains provide cognitive benefits (e.g. Sol et al 2005;Deaner et al 2007;Sol et al 2007), the present findings suggest that these benefits do not necessarily flow into increased adult survival, but may sometimes affect reproduction more.…”

“…Explaining variation in relative brain size is important, because the latter corresponds to intellectual or cognitive performance Lefebvre et al 2004;Sol et al 2005;Deaner et al 2007). Paleoanthropologists, in particular, are interested in this question, because the size of the human brain is roughly three times that of our closest relatives, common and pygmy chimpanzees, who have maintained more or less similar brain sizes since the split with the last common ancestor.…”

Mice selectively bred for high voluntary wheel running have larger midbrains: support for the mosaic model of brain evolution

“…A number of hypotheses have been generated to explain how selection may have driven changes in brain size (Francis, 1995;Barton and Harvey, 2000; de Winter and Oxnard, 2001;Hutcheon et al, 2002; Byrne and Corp, 2004;Lefebvre et al, 2004;Marino, 2005;Sol et al, 2005;Lefebvre and Sol, 2008;Rehkämper et al, 2008;Sol et al, 2008; Chittka and Niven, 2009;Roth and Pravosudov, 2009). Most, if not all, of these hypotheses suggest that selection is acting on behavior [e.g.…”

Explaining brain size variation: from social to cultural brain

“…The reason is that, in the absence of transmission to the next generation through social learning, the invented skills will merely provide a one-off fitness advantage to the inventor. The rare innovations that reflect a species' behavioral flexibility [32] and allow it to cope with environmental change [54] greatly improve fitness but are very unlikely to arise again independently in the inventor's offspring. Worse, even routine foraging, parenting or mating skills shown by any normal adult of a given species are often not spontaneously invented by maturing individuals, and only acquired when they are exposed to role models (for a review, see [55]).…”