Monkeys as good as humans in solving simple arithmetic: study

Washington, Dec 18 (UNI) Monkeys are almost as good as college students when it comes to simple arithmetic, according to a study demonstrating that a monkey's ability to perform mental addition can beat that of people.

The study carried out by the scientists at Duke University, US follows the findings by Japanese researchers earlier this month that young chimpanzees performed better than human adults at a memory game.

Prior studies have found 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 Public Library of Science journal.

For the test, two female macaque monkeys , Boxer and Feinstein, were pitched against 14 American college students with an average age of 23. Both groups carried out the same tasks of mental addition and the results almost ended in an embarrassing draw.

The test consisted of choosing the correct sum of dots shown on two consecutive computer screens. A third screen showed two boxes, one with the correct number of dots formed from adding the two previous computer screens, and another box alongside it with an incorrect number of dots.

Scientists asked the college students to choose the box with the right number of dots without counting them individually, but just using an overall visual estimate. The monkeys, meanwhile, were given a reward if they chose the box with the correct sum.

In hundreds of trials involving more than 40 different addition problems, the college students were correct 94 per cent of the time, while the two macaque monkeys scored a respectable 76 per cent. But response times for monkeys and students choosing their answers were not that different - 1,099 milliseconds for the monkeys, compared with 940 milliseconds for the students.

Intriguingly, both the students and the monkeys in the study, , took longer to come to a decision when the two boxes were close to one another in the number of dots, indicating a common approach to solving the problem, Ms Cantlon said.

''We know that animals can recognise quantities, but there is less evidence for their ability to carry out explicit mathematical tasks, such as addition. Our study shows that they can,'' she added.

Professor Elizabeth Brannon, of Duke University, said that human language makes a huge difference to the way we perform calculations because we can represent numbers as symbols that can be manipulated arithmetically.

''Much of adult humans' mathematical capacity lies in their ability to represent numerical concepts using symbolic language. A monkey can't tell the difference between 2,000 and 2,001 objects, for instance,'' Professor Brannon said.

''However, our work has shown that both humans and monkeys can mentally manipulate representations of numbers to generate approximate sums of individual objects,'' he added.

UNI