Here is an interesting article By Roger Highfield, Science Editor I’ve read on telegraph.co.uk
Young chimps have been pitted against university students in laboratory tests of working memory and - overall - the chimps won.
The assumption that the brain of a human can outperform that of close relatives is overturned today by a study that adds to research that brings chimpanzees closer to humans.
a chmp at the Primate Research Institute in Kyoto, Japan
Watch a chimp attempt the memory test in Japan
Young chimpanzees have an “extraordinary” ability to remember numerals that is superior to that of human adults.
“There are still many people, including many biologists, who believe that humans are superior to chimpanzees in all cognitive functions,” said Professor Tetsuro Matsuzawa of Kyoto University.
Prof Matsuzawa, a pioneer in studying the mental abilities of chimps, said even he was surprised by the results of his study.
He and colleague Sana Inoue report the findings in the journal Current Biology.
"No one can imagine that chimpanzees-young chimpanzees at the age of five-have a better performance in a memory task than humans.
“Here we show for the first time that young chimpanzees have an extraordinary working memory capability for numerical recollection-better than that of human adults tested in the same apparatus, following the same procedure.”
The chimps’ memory ability is reminiscent of what scientists call “eidetic imagery”, a special ability to retain a detailed and accurate image of a complex scene or pattern.
Such a “photographic memory” is known to be present in some normal human children, and then the ability declines with the age, he added.
Prof Andrew Whiten of the University of St Andrews commented: “I have seen Prof Matsuzawa’s chimpanzees performing this task and one’s first response is ‘that’s impossible!’ because they remember a sequence of numerals so well and ‘list’ them so fast. I have also attempted the task myself and my limited recall only underlines how extraordinary is the apes’ achievement.”
In the new work, the researchers took three pairs of mother and infants and taught them Arabic numerals from 1 to 9. They were then pitted them against university students in a memory task.
The chimps or humans were briefly presented with various numerals from 1 to 9 on a touch-screen monitor.
Those numbers were then replaced with blank squares, and the test subject had to remember which numeral appeared in which location and touch the squares in the appropriate order.
The young chimpanzees could grasp many numerals at a single glance, with no change in performance as the hold duration - the amount of time that the numbers remained on the screen - was varied.
In general, the performance of the three young chimpanzees was better than that of their mothers.
Likewise, adult humans were slower than all of the three young chimpanzees in their response.
For human subjects, they showed that the percentage of correct trials also declined as a function of the hold duration-the shorter the duration became, the worse their accuracy was.
One chimp, Ayumu, did the best. The researchers believe that the young chimps’ newfound ability to top humans in the numerical memory task is “just a part of the very flexible intelligence of young chimpanzees”.
One of the mothers, named Ai, was the first chimpanzee who learned to use Arabic numerals to label sets of real-life objects with the appropriate number.
Seven years ago, a study of Ai revealed that chimps are more advanced with numbers than pre-school children.
In the previous study she could remember the correct sequence of five random numbers between zero and nine.
Adult humans can easily memorize phone numbers and post codes if they are up to seven items long, but beyond that they find it harder.
Ai was born in Africa and is believed to have been born around October 1976. She was brought to the research center at the age of one, where, at age two, she began learning symbols by using a computer.