Japanese researcher Tetsuro Matsuzawa of Kyoto University said the findings dispel commonly held beliefs that “humans are superior to chimpanzees in all cognitive functions".

Matsuzawa, a pioneer in studying the mental abilities of chimps, admitted that even he was surprised.

He and colleague Sana Inoue will report the results in tomorrow's issue of the journal Current Biology.

Three chimps were found to be able to perform a first memory test faster than human volunteers, although with no more accuracy.

The chimp champ, Ayumu, who performed best, was then pitted against nine college students in a second test.

Researchers found that Ayumu was better at taking in a whole pattern of numbers at a glance.

Matsuzawa said that even with six months of training, three students failed to catch up with the three chimps.

“No one can imagine that chimpanzees - young chimpanzees at the age of 5 - have a better performance in a memory task than humans,