A study by Japanese researchers in the Dec. 4 issue of Current Biology claims that chimpanzees outperformed humans on a test of short-term memory.
The chimps and the humans were briefly shown numerals from 1 to 9 on a touch-sensitive screen, then the numbers were covered with blank squares. The test-takers had to recall which numeral was under which square, in order.
The young chimpanzees could grasp many numerals at a glance, with no change in performance as the hold duration–the amount of time that the numbers remained on the screen–was varied, the researchers found. 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.
But Charan Ranganath, associate professor of psychology at the Center for Neuroscience who studies human memory, was not persuaded when I talked to him about the study.
Ranganath points out that based on the paper, the chimps were extensively trained in the task, while the humans were identified as college students, and it’s not clear if they were trained at all. And then the researchers picked the best performers among the chimps and compared them to an average of the humans.
On the other hand, it’s quite impressive that the chimps could be trained to accomplish the memorization task at all, he said.