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Chimps outsmart uni students


Young chimpanzees are better than humans at memorising sequences of numbers, a skill chimps lose as they get older (Source: iStockphoto)

chimps outsmart students Young chimpanzees are better than university students at playing a computer game that tests numerical memory, a new study shows.

The scores, revealed today in the journal Current Biology, weren't even close.

One young chimp named Ayumu who, in his off time, buys his own vending machine snacks, scored 76% correct in one game. The adult human average for the same game was 36%.

The study is one of the first to demonstrate that, at least under certain circumstances, chimp memory may be better than that of humans.

"No human adults reached Ayumu's level," says co-author Professor Tetsuro Matsuzawa, director of Kyoto University's Primate Research Institute.

"The young chimpanzees are better than human adults in a memory task," says Matsuzawa, who collaborated with the institute's Sana Inoue on the paper.

"Young chimpanzees quickly grasp many numerals at a glance, with no decline in performance as the hold duration is varied."

Playing games

Matsuzawa is referring to a game that works like the popular card-match memory games on many home computers.

In this case, however, the three young chimp players, their mothers and human students were each shown a series of numbers from 1 to 9 on the screen.

The numbers were then replaced by blank squares, which the players had to touch based on their knowledge of numerical sequences.

For example, if the numbers 2,3,5,8 and 9 appeared on the screen, the player had to touch the corresponding blank squares in that order.

What confused the human players was the length of time that the numbers first appeared on the screen. The shorter the duration, the worse they scored.

"Ayumu's performance was kept constant regardless of the duration of looking at the numerals," says Matsuzawa, who even failed to stump the chimp when he flashed five numbers for just 210 milliseconds.

Special type of memory

The mother chimps and the adult humans all played worse than the young chimpanzees, probably because of a phenomenon called "eidetic imagery".

"[This is] a special memory capability to retain an accurate, detailed image of a complex scene or pattern," he says.

Many human children have the skill, which declines with age.

While chimps in the wild obviously aren't playing computer games, they use the same skills to assess numbers of fruits ripening on trees, hierarchical positions within their troops, and to evaluate locations and numbers of enemies "in the bush at a glance".

Matsuzawa theorises there is a mental trade-off between memory and symbolisation, especially as it relates to language, in humans. This may cause the apparent memory lapses later.


Dr James Anderson, a member of the Scottish Primate Research Group at the University of Stirling, says the new research "is impressive on several levels".

"Of course there is the striking finding that immature chimpanzees outperform both adult chimpanzees and adult humans in the numerical sequence task," Anderson says.

"This naturally leads us to speculate on the development of the cognitive abilities involved in this task, in terms not only of individual development but also species-typical abilities," he says.

"[The study is also an] excellent example of how good laboratory-based experiments can reveal abilities that would be extremely difficult, if not impossible, to uncover through purely observational studies."

Tags: environment, animals, animals, mathematics, neuroscience