Beyond the cortex–integrating hippocampal function into the Social Brain Hypothesis to explain advanced cognition

The Social Brain Hypothesis (SBH) connects primate brain size to social complexity but faces empirical limitations. We propose expanding the SBH by incorporating hippocampal functions across species, demonstrating how cognition emerges from both social and ecological pressures. This extended framework moves beyond cortical-centric models, providing a comprehensive understanding of brain evolution and the origins of human cognitive abilities, including language.