Study shows animals with larger brains are best problem solvers

Jan 26, 2016

Photo credit: Sarah Benson-Amram


Why did some species, such as humans and dolphins, evolve large brains relative to the size of their bodies? Why did others, such as blue whales and hippos, evolve to have brains that, compared to their bodies, are relatively puny?

It has long been thought that species with brains that are large relative to their body are more intelligent. Despite decades of research, the idea that relative brain size predicts cognitive abilities remains highly controversial, because there is still little experimental evidence to support it. However, a paper released today describes a massive experiment that supports the theory.

Sarah Benson-Amram, an assistant professor in the Department of Zoology and Physiology at the University of Wyoming, is the lead author on a new paper, titled “Brain size predicts problem-solving ability in mammalian carnivores.” It shows that carnivore species with larger brains relative to their body size are better at solving a novel problem-solving task. The paper appears in the Proceedings of the National Academy of Sciences, one of the world’s most prestigious scientific journals.

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9 comments on “Study shows animals with larger brains are best problem solvers

  • I am astonished that the key variable is (brain size) / (body weight). I would have expected it to be simple brain size as Dr. John Lilly argued.

    Perhaps there is some way to measure brain size not involved in controlling the body. A trex was able to control its body with a walnut sized brain.

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  • The only thing I know about animal brain size is that a domestic animal’s counterpart in the wild has better problem solving abilities; there’s no need to elaborate on why that is, because the reason is obvious.

    To digress slightly, the most intelligent person I’ve ever known has been strictly vegetarian since she was sixteen; that’s to say that she hasn’t knowingly eaten any part of any animal since she was that age; she is now sixty two!

    She’s also the most energetic individual I’ve ever known; would she have been even brighter and have had more vitality if she’d eaten meats I wonder?

    Currently, the received hypothesis on that matter is yes; but I doubt she could have been.

    But since it’s not possible to extrapolate from the individual to the rest of humanity, I suppose that she must be very exceptional.

    Sorry mods, I’ve waffled somewhat.

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  • @OP – “Brain size predicts problem-solving ability in mammalian carnivores.” It shows that carnivore species with larger brains relative to their body size are better at solving a novel problem-solving task.

    That is probably so within species, and within comparable environmental conditions.

    It goes out of the window once we compare mammals with the more intelligent birds, which have evolved with weight reductions a priority enabling flight.

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  • Neuron density is constant in primate brains, so brain weight is proportional to the number of neurons. (A further important factor would be synaptic count per neuron). Other species do not scale. Rodent brains by contrast seem to bulk up to fill available space. A rat with our neuron count would need a 35Kg brain. (Is it all just more myelin around bigger neurons, to maintain response time?)

    There might be different evolutionary pressures solved by brute force and ignorance as much as intellectual niceties…

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  • Come on, man. You have provided us with nothing more than a single anecdotal data point. Your doubts as to whether or not your friend might be more intelligent with more or less meat are even less meaningful than this data point. You know how this works: none here would convert, should a christian tell us a story about their mate recovering from cancer after praying…

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  • I have seen brain size/ body mass graphed in a nature documentary. Those with the greatest value for this ratio, regardless of absolute body mass (or brain size) appeared to be the most “intelligent”, meaning adaptably able to solve problems. The winners included the New Caledonian Crow (a tool-maker and user), the Kea (New Zealand Parrrot), along with the usual suspects – humans, chimps, dolphins.

    Interesting in that the “bird brains” clearly outperformed mans best friend in some demonstration challenges. Though that might have been a set-up.

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  • I know that woman, Stafford. You’re right! Remarkable woman. I just had tea with her this afternoon. We had a lovely chat. She hasn’t lost one bit of her acuity.

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  • Thank you prmcdon, I now have the catchy title I’ve been seeking for my autobiography, ‘A Collection of Random Single Anecdotal Data Points’. Available from all good booksellers soon.

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