The evolution of complementary cognition: humans cooperatively adapt and evolve through a system of collective cognitive search

We propose a new theory of human cognitive evolution, which we term Complementary Cognition. We build on evidence for individual neurocognitive specialization regarding search abilities in the modern population, and propose that our species cooperatively searches and adapts through a system of group-level cognition. This paper sets out a coherent theory to explain why Complementary Cognition evolved and the conditions responsible for its emergence. Using the framework of search, we show that Complementary Cognition can be contextualized as part of a hierarchy of systems including genetic search and cognitive search. We propose that, just as genetic search drives phenotypic adaptation and evolution, complementary cognitive search is central to understanding how our species adapts and evolves through culture. Complementary Cognition has far-reaching implications since it may help to explain the emergence of behavioural modernity and provides a new explanatory framework for why language and many aspects of cooperation evolved. We believe that Complementary Cognition underpins our species' success and has important implications for how modern-day systems are designed.