A college education doesn't give you much of an edge over a monkey when it comes to doing some basic arithmetic, according to a study released Monday that underscores the surprising mental agility of our simian relatives.
In a rapid fire test of mental addition, monkeys performed almost as well as college students, showing they're no slouches when it comes to number crunching.
The macaques got their sums right 76 percent of the time, while the students got the correct answer 94 percent of the time in a series of increasingly challenging maths tests.
"We know that animals can recognize quantities, but there is less evidence for their ability to carry out explicit mathematical tasks, such as addition," said Jessica Cantlon, a researcher at Duke University Center for Cognitive Neuroscience in Durham, North Carolina.
"Our study shows that they can."
The study in the Public Library of Science Biology comes just a couple of weeks after Japanese researchers revealed that young chimps outperformed college students in tests of short-term memory.
The young chimps surprised the Japanese investigators by being able to retrace patterns of numbers flashed up on a computer screen faster than their human rivals.
The current study, according to researchers, goes one step further by showing that primates can process information as well as reproduce it, and that there's more to our closest living relatives than "monkey see, monkey do."
It also suggests that basic arithmetic may be part of our shared evolutionary past.
"Humans have some pretty sophisticated problem-solving skills, but this study suggests they may also be able to tap into some primitive method of making calculations," said Cantlon.
She said the assumption is that the monkeys are using the same kind of primitive non-verbal mathematics.
For the test, the monkeys and students were seated at a computer and shown a screen with a certain amount of dots, followed by a screen with another amount of dots.
The third screen contained two boxes, one containing the sum of the first two sets of dots, and one containing a different number. The monkeys were rewarded with the soft drink, Kool-Aid, for selecting the box containing the correct sum of the sets.
The students were told not to verbally count the dots.
The average response time for both the college students and the macaques was one second, and at least in one other respect, their performance was surprisingly similar.
Both the monkeys and the students took longer to make a choice and made more mistakes when the two choice boxes were close in number.
"We call this the ratio effect," said Cantlon. "What's remarkable is that both species suffered from the ratio effect at virtually the same rate."