’Selfish brain’ wins out when competing with muscle power, study finds

New research on our internal trade-off when physical and mental performance are put in direct competition has found that cognition takes less of a hit, suggesting more energy is diverted to the brain than body muscle. Researchers say the findings support the 'selfish brain' theory of human evolution. A well-fuelled brain may have offered us better survival odds than well-fuelled muscles when facing an environmental challenge - Danny Longman Human brains are expensive - metabolically speaking. It takes lot of energy to run our sophisticated grey matter, and that comes at an evolutionary cost. Now, a new investigation into the immediate trade-off that occurs inside us when we have to think fast and work hard at the same time is the first to demonstrate that - while both are impaired - our mental ability is less affected than our physical capacity. Researchers say that the findings suggest a "preferential allocation of glucose to the brain", which they argue is likely to be an evolved trait - as prioritising quick thinking over fast moving, for example, may have helped our species survive and thrive. Scientists from the University of Cambridge's PAVE (Phenotypic Adaptability, Variation and Evolution) research group tested 62 male students drawn from the University's elite rowing crews.