For over a century, scientists have made remarkable progress in understanding how human intelligence works: from identifying cognitive abilities through psychological testing to mapping brain networks with modern imaging technology and discovering genetic influences through DNA analysis. However, this progress has been largely driven by technological advances rather than guided by a unifying theory. A new study proposes an evolutionary framework that brings all these pieces together, suggesting we should study human cognition the same way biologists study other evolved traits, which is by asking four key questions about evolutionary pressures, function, biological mechanisms, and development.
The framework focuses on two major brain networks that make humans cognitively unique. The Default Mode Network (DMN) is active when we daydream, imagine future scenarios, or think about ourselves and others, essentially our “internal mental world.” The Frontoparietal Network (FPN) kicks in when we need to solve problems, focus attention, or engage in complex reasoning. These networks don’t work in isolation but interact with other brain systems to produce our most sophisticated abilities: abstract thinking, planning for the future, self-awareness, and fluid reasoning. By understanding how these networks evolved, what environmental pressures shaped them, and how they develop from infancy through adulthood, researchers can gain deeper insights into human intelligence itself.
The study also reveals fascinating patterns in human genetic history. Analysis of ancient DNA shows that genes associated with intelligence and educational success increased as our ancestors shifted from hunting and gathering to agriculture, likely because surviving in complex agricultural societies required more sophisticated cognitive abilities. Interestingly, these same genetic markers tend to decline during periods of peace and prosperity (like when life becomes easier and child mortality drops, the evolutionary advantage of exceptional cognitive abilities diminishes). This pattern has repeated throughout history, from the rise and fall of the Roman Empire to modern populations in Iceland, the UK, and the US.
This evolutionary perspective has profound implications for understanding both individual differences and modern challenges in education and child development. It suggests that the cognitive abilities we value today were shaped by thousands of years of environmental challenges and social competition. Understanding the environmental conditions necessary for optimal brain network development (including not just education but also nutrition, health, and social experiences) could help us better support cognitive development in children and potentially delay cognitive aging in adults. Moreover, recognizing that certain brain adaptations evolved for ancestral environments helps explain why some individuals struggle in modern contexts (what was adaptive in a harsh, unpredictable environment may create difficulties in today’s more stable world).
Link to full article: https:/​/​doi.org/​10.65550/​001c.154815