Global climate change and Homo brain size

Changes to brain size in hominins constitute a crucial evolutionary trend, yet the underlying mechanisms behind those changes are not well understood. In this dataset, climate change was considered as an environmental factor using four paleoclimate records testing temperature, humidity, and precipitation against changes to brain mass in 298 Homo specimens over the past fifty thousand years. Across regional and global paleoclimate records, brain mass in Homo averaged significantly lower during periods of climate warming as compared to cooler periods. To a smaller degree, humidity and precipitation levels were also predictive of brain mass, with arid periods associated with lower brain mass in Homo. The findings suggest a relationship between climate change and brain size in Homo that is driven by natural selection in response to environmental stress.