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Suzana Herculano-Houzel

Associate Professor of Psychology

Neuroscientist and international expert in how brain size and structure affect cognition and longevity in animals.


Suzana Herculano-Houzel, P.I. ( is Associate Professor of the Departments of Psychology and Biological Sciences at Vanderbilt University since 2016. She was previously an Associate Professor at Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Brazil, between 2002-2016. She majored in Biology at Universidade Federal do Rio de Janeiro (1992), holds an M.Sc. in Neuroscience (Case Western Reserve University, 1995, with Story Landis), and a Ph.D. in Neuroscience (Université Paris VI, 1999, with Yves Frégnac and Max-Planck-Institut for Brain Research, with Wolf Singer). In Brazil, she was a Scientist with the National Research Council (CNPq) from 2007 to 2016; Young Scientist of the State of Rio de Janeiro (FAPERJ, 2007-2009) and Scientist of the State of Rio de Janeiro (FAPERJ) between 2009 and 2016. In 2010, she was a recipient of the Scholar Award in Understanding Human Cognition, James S. McDonell Foundation. She is the author of six books (in Portuguese) for the general public on the neuroscience of everyday life, with over 80,000 copies sold, was the writer and presenter of the TV series Neurológica (Fantástico, Rede Globo de Televisão) between 2008 and 2011, and remains a regular writer for the newspaper Folha de São Paulo since 2006.

Media Appearances

  • Do Crows Possess a Form of Consciousness?

    The crows’ neurons “have activity that represents not what was shown to them, but what they later have seen—whether or not that is what they were shown,” Suzana Herculano-Houzel, a neurobiologist at Vanderbilt University who published an analysis of the study in Science, tells Stat. This secondary layer of processing of the visual stimulus occurs in the time between when the stimulus appears on the screen and when the crow pecks its answer.

    September 30th, 2020

  • Crows Are Self-Aware and 'Know What They Know,' Just Like Humans

    In an analysis in the same issue of Science, another researcher, Suzana Herculano-Houzel of Vanderbilt University, makes a critique of the study’s hypothesis. The structure being studied, she says, could resemble another structure because of physical properties more than a shared evolution or an indication of extremely early consciousness. The size of the structures matter a great deal, too. “[T]he level of that complexity, and the extent to which new meanings and possibilities arise, should still scale with the number of units in the system,” Herculano-Houzel explains. “This would be analogous to the combined achievements of the human species when it consisted of just a few thousand individuals, versus the considerable achievements of 7 billion today.”

    September 28th, 2020

  • Your big brain makes you human – count your neurons when you count your blessings

    Here’s something new to consider being thankful for at the dinner table: the long evolutionary journey that gave you your big brain and your long life. Courtesy of our primate ancestors that invented cooking over a million years ago, you are a member of the one species able to afford so many cortical neurons in its brain. With them come the extended childhood and the pushing century-long lifespan that together make human beings unique.

    November 26th, 2019

  • How Human Smarts Evolved

    Suzana Herculano-Houzel spent most of 2003 perfecting a macabre recipe — a formula for brain soup. Sometimes she froze the jiggly tissue in liquid nitrogen, and then she liquefied it in a blender. Other times she soaked it in formaldehyde and then mashed it in detergent, yielding a smooth, pink slurry.

    August 20th, 2018

  • To Unlock the Brain’s Mysteries, Purée It

    One day in June 2012, at São Paulo’s international airport, Suzana Herculano-Houzel hauled two heavy suitcases onto an X-ray-machine conveyor belt. As the luggage passed through the scanner, the customs agent’s eyes widened. The suitcases did not contain clothes, toiletries or any of the usual accouterments of travel. Instead, they were stuffed with more than two dozen curiously wrapped bundles, each enclosing an amorphous blob suspended in liquid. The agent asked Herculano-Houzel to open her bags, suspecting that she was trying to smuggle fresh cheese into the country; two people had been caught doing exactly that just moments before. “It’s not cheese,” Herculano-Houzel said. “It’s only brains.”

    December 14th, 2017

  • Dear cat person, dogs are officially smarter. Regards, science

    It ends today. Champions from both camps can rest their weary heads knowing they fought the good fight and finally find some peace in the fact that the battle is officially over. Dogs, confirms science, are smarter than cats. Dr Suzana Herculano-Houzel, associate professor of psychology and biological sciences at Vanderbilt University, believes "the absolute number of neurons an animal has, especially in the cerebral cortex, determines the richness of their internal mental state and their ability to predict what is about to happen in their environment based on past experience." Dogs, pound for pound of brain, have a lot more neurons than cats. More than double, in fact. While cats can sleep soundly in the knowledge (and they will) that they have a respectable 250 million cortical neurons in their adorable noggins, dogs boast an impressive 530 million. And that, according to Herculano-Houzel, makes them far brainier. Side factoid: you and I can claim about 16 billion neurons each kicking around in the old thinker.

    December 6th, 2017

  • Bird Brains Have as Many Neurons as Some Primates

    Although many in the field expected the bird brain could be densely packed, the extent came as a surprise to the study authors. “My expectation was simply that bird brains should be different from mammals in size and number of neurons,” says neuroscientist Suzana Herculano-Houzel, now at Vanderbilt University, one of the senior authors on the paper. “But we didn’t have any idea that the difference would be so extreme that in a parrot brain you would have as many neurons as in a mid-size primate.”

    June 17th, 2016


Ph.D., Université Pierre

M.Sc., Case Western Reserve University

B.Sc., Universidade Federal do Rio de Janeiro


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