Rhesus macaque monkeys performed nearly as well as college students at quick mental addition, researchers reported Monday, adding to the evidence that non-verbal math skills are not unique to humans.
The study from Duke University follows findings by Japanese researchers earlier this month that young chimpanzees performed better than human adults at a memory game.
Prior studies have found that non-human primates can match numbers of objects, compare numbers and choose the larger number of two sets of objects.
"This is the first study that looked at whether or not they could make explicit decisions that were based on mathematical types of calculations," said Jessica Cantlon, a cognitive neuroscience researcher at Duke whose work appeared in the open-access journal PLoS Biology.
"It shows when you take language away from a human, they end up looking just like monkeys in terms of their performance," Cantlon told Reuters in a telephone interview.
Her study pitted Boxer and Feinstein — two female rhesus macaques named after U.S. Sens. Barbara Boxer and Dianne Feinstein of California — against 14 Duke University students.