“My undergrad curriculum didn’t include anything about brains. Her positivity paid off when she left Brazil for Case Western in Cleveland, originally intending to study molecular genetics. “It was a terrible idea because there was no market for it,” she says. Despite the chronic lack of funding for science in Brazil, her parents encouraged her to follow her passion for biology. She was raised in Rio by academic parents, her mother a sociologist and her father an economist. “I was born an optimist, to the point that it annoys people,” she laughs. Herculano-Houzel talks with an easygoing humor and an infectious love of science. “She is absolutely innovative in thinking about what these results mean.” QUEST FOR THE TRUTH What sets Herculano-Houzel apart, Kaas says, is not just the data she’s uncovered, but how she has analyzed it to discover previously unknown truths about our most powerful organ. “There is a lot of data on brain size, but if you don’t know the number of neurons, you are limited in what you can theorize about,” says Jon Kaas, Gertrude Conaway Vanderbilt Distinguished Professor of Psychology.
Herculano-Houzel summarized her findings last year in a book, The Human Advantage: A New Understanding of How Our Brain Became Remarkable (MIT Press), around the same time she joined the psychological sciences department at Vanderbilt. To a nonscientist that may seem like a small distinction, but as Herculano-Houzel points out, “The difference is an entire baboon brain and change.” Since first pioneering the new technique, she has applied it to dozens of animal species, introducing a whole new frontier in evolutionary neuroscience. The resulting number for humans turned out to be 86 billion. Her search for the answer to a seemingly simple question ultimately steered Herculano-Houzel back into academia and soon led her to develop a new method to measure the number of neurons in the brain.
Everyone thought everyone else already knew, so nobody bothered anymore.” “It was a bunch of intuitions people heard about second- or thirdhand. “We really didn’t know the first thing about the actual number,” Herculano-Houzel says. Scientists routinely bandied about the number 100 billion, but that seemed based on an order-of-magnitude estimate extrapolated from only parts of the brain. The more she looked, however, the more myths she found.
Consequently, she began searching through the scientific literature for an answer. “It’s one of those pieces of popular culture that just keeps going around.”Ī neuroscientist with a master’s degree from Case Western Reserve University and a doctorate from Universite Pierre et Marie Curie in Paris, Herculano-Houzel figured the first step to disproving the myth was to determine exactly how many neurons the brain actually contains. “Which is completely wrong! We use 100 percent of the brain, 100 percent of the time,” Herculano-Houzel says. The persistence of that myth proved so galling to Suzana Herculano-Houzel, Vanderbilt associate professor of psychology and biological sciences, that when she worked as a science educator at the Museu da Vida in Rio de Janeiro, she conducted a survey in 2002 and found that 60 percent of the college-educated public believed it.
#HOW MANY NEURONS IN THE BRAIN HOW TO#
That myth goes back at least as far as Dale Carnegie’s 1936 book, How to Win Friends and Influence People, and has cropped up as recently as the 2014 Scarlett Johansson movie Lucy. Take the canard that humans use only 10 percent of their brains, leaving vast reservoirs of gray matter untapped.