In this engaging work, Herculano-Houzel, a biologist from the Federal University of Rio de Janeiro, ponders whether human brains are extraordinary. Using data mostly collected in her own laboratory via a technique she devised for accurately counting the number of neurons in brains, she concludes that “our brain is remarkable, yes—but not special in the sense of being an exception to the rules of evolution.” She goes on to explain how primate brains are configured differently from non-primate brains, with the former having a much greater density of neurons than the latter, leading to greater cognitive capabilities. She also demonstrates that among primates, great apes are the outliers, not humans: great apes have smaller brains than expected based solely on body size, while humans possess the predicted size. In a relatively short but absolutely critical section, Herculano-Houzel draws on the work of others to explain that the human brain’s neuron density likely arose because humans learned how to cook food, which permits significantly more energy to be gained from a given amount of raw material. Herculano-Houzel puts her expertise as a science journalist to good use, though her heavy reliance on statistical patterns may put off some readers. (Apr.)
Suzana Herculano-Houzel is Associate Professor at Vanderbilt University in the Departments of Psychology and Biological Sciences at Vanderbilt University.