In a series of trials conducted by psychologists at the University of Rochester, a small troop of olive baboons was shown to be generally successful at choosing which of two plastic cups contained more peanuts.
According to the study, the baboons were not counting the legumes one-by-one, a skill that only humans are known to have for quantities greater than three or four.
Instead, the researchers believe that the primates used a rough “eyeballing” technique.
This is similar to the way that human toddlers, who have not yet learned to properly count, size up differences in quantity, says Jessica Cantlon, co-author of the study, which was published in the journal Frontiers in Psychology.
“This tells us that non-human primates have in common with humans a fundamental ability to make approximate quantity judgments,” she says.
“Humans build on this talent by learning number words and developing a linguistic system of numbers, but in the absence of language and counting, complex math abilities do still exist.”
Photo: University of Rochester