Aurich Lawson
We often think math skills are unique to humans, but in fact scientists have found that many animal species — including lions, chimpanzees, birds, bees, ants and fish — seem to possess at least a rudimentary counting ability or sense of number. Crows can understand the concept of zero. And a study published in April found that both stingrays and cichlids can take this rudimentary “numerosity” to the next level, by simply performing addition and subtraction for a small number of objects (in the range of 1 to 5).
The latest study’s conclusion doesn’t surprise cognitive psychologist Brian Butterworth, professor emeritus at University College London and author of a new book, Can fish count? What animals reveal about our unique mathematical mind†
“There are many animals that can add and subtract,” Butterworth told Ars. “Bees can do that. Bees can also represent zero. So I’m not surprised that stingrays and cichlids can do it.” His book explores how the ability to process mathematical information and extract numerical data from their environment is critical to an animal’s ability to survive and thrive. In fact, there may just be an innate understanding of math at the most basic level passed down the evolutionary chain from our most distant common ancestors.
Butterworth’s interest in the number sense of animals has its origins in his early work as a psycholinguist in the 1980s. When he met an Italian psychologist named Carlo Semenza at a conference, he became intrigued by human language disorders, such as aphasia, and mathematical cognitive disorders, especially dyscalculia. Christian Agrillo, one of Semenza’s students who came to work at Butterworth, was an expert on fish and gave a talk on his research that showed that some small fish have numerical abilities. Butterworth was fascinated and eventually developed a parallel research program focusing on the numerical skills of fish. “And once you get into fishing, there are all kinds of other animals that pique your interest,” he said.
Butterworth is still studying the genetics and neuroscience underlying the number sense in fish, with plans to conduct brain imaging studies later this year. And how do you go about peeking into a fish’s brain while it counts? “First of all, you must [biofluorescent] gene, where when neurons connect, when synapses connect, they light up,” Butterworth said. “Then you have to have a fish whose head is transparent — a larval version of the fish. That way you can see with a microscope what’s going on in the fish’s brain, while choosing the size of the aquarium with more objects in it.”
Ars sat down with Butterworth to find out more.
