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

TLDR

The widely held hypothesis that enlarged brains evolved as an adaptation to cope with novel or altered environmental conditions lacks firm empirical support. The study tests whether large‑brained bird species survive better than small‑brained ones when introduced to nonnative locations. The authors use a global database of over 600 introduction events to assess survival outcomes relative to brain size. The analysis shows that birds with larger brains relative to body mass are more successful at establishing in novel environments, and that this advantage is due to increased innovation propensity rather than noncognitive mechanisms, providing strong evidence that enlarged brains evolved to cope with environmental change.

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 large-brained 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.