http://www.nytimes.com/2007/12/04/science/04obchim.html?_r=1&ref=science&oref=slogin
December 4, 2007
OBSERVATORY
Chimps Exhibit Superior Memory, Outshining Humans
By HENRY FOUNTAIN
Spend even a little time around chimpanzees, and you begin to realize how
intelligent they are. But can they outshine humans in brain power? Most
humans would scoff at that.
But researchers have shown that young chimps outperform adult humans in a
memory test, a Concentration-like game using numerals on a computer
screen.
We were very surprised to find this,
Tetsuro Matsuzawa of the Primate Research Institute at Kyoto University
said.
But it
s a very concrete, simple fact. Young chimps are superior to human adults
in a memory task.
When the researchers went to see if there was a difference with chimps
younger than 6, the animals had a touch screen where scattered numerals
appeared for up to two-thirds of a second and were then masked by white
squares. With the shortest exposure time, about a fifth of a second, the
chimps had an 80 percent accuracy rate, compared with adult humans
40 percent. The findings are described in Current Biology.
Dr. Matsuzawa said the ability reminded him of the phenomenon called
eidetic imagery, in which a person memorizes details of a complex scene at
a glance. This so-called photographic memory is present in a very small
number of children, and is often associated with autism.
Dr. Matsuzawa speculated that perhaps somewhere back in common evolution,
humans and chimps had this ability. But humans lost it because they gained
something else, communicating through a complex language.
As Ai demonstrates, adult chimps lose the ability, too. Dr. Matsuzawa
suggested that as the chimps age, their memory capability is otherwise
occupied.
Dr. Matsuzawa and a colleague, Sana Inoue, first trained chimps to
recognize the numerals 1 through 9 in sequence. Ai, the first chimp
trained, an adult female was found with a memory capability equal to that
of adult humans.