Counting Crows: Evidence for Hard-Wired, Inborn Ability to Detect Numerical Sets

“The Great Book of Nature is written in mathematical language” –Galileo Galilei (1)

carrion crow (corvus corone) headshot portrait against a blue background

Carrion Crow (Corvus corone)

If mathematics is the language of the universe, might we find the ability to do math hard-wired in species?

Research in primates has demonstrated that even without training, humans and monkeys possess numerosity, the ability to assess the number of items in a set (2,3).

A paper in Current Biology from Wagener and colleagues provides evidence that crows are born with a subset of neurons that are “hard wired” to perceive the number of items in a set (4). This work provides yet more evidence supporting a hypothesis of an innate “number sense” that is provided by a specific group of “preprogrammed” neurons.

In this study, Wagener’s group measured the responses of single neurons in two “numerically naïve” crows to color dot arrays. They measured neurons in the endbrain region known as the niopallium caudolaterale (NCL), which is thought to be the avian analog of the primate prefrontal cortex. They found that 12% of the neurons in NCL specifically responded to numbers and that specific neurons responded to specific numbers of items with greater or lesser activity.

This is the first such study to investigate the idea of an innate “sense of number” in untrained vertebrates that are not primates, and as such it suggests that a hard-wired, innate “sense of number” is not a special feature of the complex cerebral cortex of the primate brain but is an adaptive property that evolved independently in the differently structured and evolved end brains of birds.

Many questions remain. Are there similarities in the actual neurons involved? What does learning do on a physiological level to these neurons: Increase their number, increase connections to them?  What other vertebrates have similar innate mechanisms for assessing numbers of items? What about other members of the animal kingdom that need to have a sense of number for social or foraging behavior? How is it accomplished?

And finally, one last burning question, if birds are dinosaurs, does that mean that dinosaurs perished because they didn’t do their math homework? Asking for an eleven-year-old I know.

  1. Tyson, Peter. (2001) Describing Nature with math. NOVA 
  2. Izard, V. et al. (2009) Newborn infants perceive abstract numbers PNAS USA 106, 10382–85.
  3. Viswanahtan, P. and Neider, A. (2013) Neuronal correlates of a visual “sense of number” in primate parietal and prefrontal cortices. PNAS USA 110, 1118–95.
  4. Wagnener, L. et al. (2018) Neurons in the endbrain of numerically naïve crows spontaneously encode visual numerosity Cur. Biol. 28, 1–5.
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Michele Arduengo

Social Media Manager at Promega Corporation
Michele earned her B.A. in biology at Wesleyan College in Macon, GA, and her PhD through the BCDB Program at Emory University in Atlanta, GA. Michele manages the Promega Connections blog. She enjoys leisure reading, writing creative nonfiction and knitting, and the occasional cross-country skiing jaunt.

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