Neuroplasticity: Biological Evolution’s Contribution to Cultural Evolution

Abstract

The increase in brain size in humans relative to other primates is due to an increase in the number of cells and their interconnections. These increases exponentially increase the number of possible combinations of cells. Brain functions, including behavior and cognition, are based on functional systems that integrate widely distributed brain areas and millions of individual cells. The connections among neurons that constitute these functional systems are shaped by neuronal activity induced by stimulation from the environment. The powerful post-natal shaping of brain structure and function by environmental input during childhood continues much longer in humans than in other animals. Moreover, humans are the only animal that shapes the environment that shapes its brain. Today, most children are raised in largely human-made environments. This process of creating different neural structures through transgenerational alterations in the rearing environment is cultural evolution. By young adulthood, established neurocognitive structures are self-maintaining and the biological processes that support change in neuronal connections become less powerful. As a result, the homology between internal neurocognitive structures and the external environment achieved in childhood by the brain shaping itself to the environment is maintained in adulthood by acting on the environment to make it match established internal structures.