London, Dec 18 : A new study conducted by researchers at Duke University in Durham, North Carolina, has found a monkey's ability to handle basic addition is similar to that of humans.
A new study conducted by researchers at Duke University in Durham, North Carolina, has found a monkey's ability to handle basic addition is similar to that of humans.
Researchers conducted study with two rhesus macaques and fourteen undergraduates.
In the mathematical competition between man versus macaque, students bested the monkeys for overall accuracy at 94 percent to 76 percent. However, response times during a computerized test of addition were approximately the same in the two groups. Both groups were more likely to stumble as the magnitude of the sums increased.
Researchers said that such similarities suggest an evolutionary continuity between basic mathematical skills in humans and other primates.
Jessica Cantlon of Duke University in Durham, North Carolina, said the fact that monkeys can handle basic arithmetic is not in itself new, as it had been suggested by previous work. If monkeys watch as lemons are placed behind a screen, for example, they will stare longer at the fruit if the screen is lifted to reveal an incorrect sum of lemons.
Their apparent surprise when the number of lemons revealed isn't what was expected suggests the presence of rudimentary mathematical ability.
"It's not math in the sense of a symbolic procedure, the way that humans typically think of math. It's a more primitive form," Nature quoted Cantlon, as saying.
Cantlon and her colleague, neuroscientist Elizabeth Brannon, examined the extent of these abilities by training monkeys to watch as two groups of dots were displayed briefly on a computer screen. Subjects were then presented with two new sets of dots and asked to select the one that represented the correct sum of the previous set. The task didn't get too hard: the highest sums were always less than 20.
The dots were flashed onto the computer screen for only half a second - too quick for humans to use their verbal skills to count them.
"If you make them respond really rapidly, they don't have enough time to perform some sort of verbal counting algorithm. If you really push the system, you can get a performance out of it that's much more primitive," Cantlon said.
Both scientists also varied the size and position of the dots, so that study participants could not use estimates of surface area or pattern recognition to help in choosing the correct sum.
Both groups needed about a second to come up with an answer. Accuracy in both groups declined as the numbers of dots got larger, and when the two possible answers were close together in value (determining if 10 + 10 dots = 19 or 20, for example, would be much harder than working out if 10 + 10 dots = 12 or 20).
"When the two [possible answer] numbers get larger and closer together, the probability of confusing them increases. That was the case in both humans and monkeys," Cantlon said.
Marc Hauser, a cognitive scientist at Harvard University, said the study beautifully extends previous findings. But the two monkeys performed thousands of trial runs before being tested. A critical next step will be to test the animals in the absence of training,
"This will be important especially since the human-animal comparison often breaks down because the former are tested without training and the latter with training," he added.
The results are published this week in PLoS Biology. (ANI)
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