In Tests, Baboons Show Signs of Abstract Thinking

Baboons in laboratory experiments showed hints of abstract thinking by picking out various images on a computer screen, a surprising finding that raises new questions about evolution and what distinguishes humans from the rest of the animal kingdom.

Scientists in France and the United States cautioned that only two baboons participated in the comparative tests, and those monkeys were veterans of earlier cognitive experiments.

And, the baboons had to repeat the tests thousands of times to learn how sets of images were the same or different.

Even so, researchers said, the results suggest baboons are capable of analogical judgment--the kind of “this-is-to-that” comparisons that psychologists say is fundamental to reasoning.

Previously, chimpanzees were the only nonhuman primates to demonstrate similar skills in experiments.

“Although discriminating the relation between [images] may not be an intellectual forte of baboons, it nevertheless is within their ken,” reported Joel Fagot of the Center for Research in Cognitive Neuroscience in Marseilles, France.

Fagot’s research, with Edward Wasserman and Michael E. Young of the University of Iowa, was published in the October issue of the Journal of Experimental Psychology.

Other researchers said the finding is important because it shows that understanding the relationships between things--what is the same and what is different--does not necessarily require language to identify or describe them.

The experiment holds “clear implications for understanding the evolution of the mind,” said psychologist Kimberly Kirkpatrick of the University of York in England. “The baboon’s ability to match relations may be a precursor to human analogical thinking.”

In the experiments, researchers showed the baboons sets of 16 images. One set comprised rows of pictures--the sun, a light bulb, a brain, a hand. Another set repeated a single image--all telephones, for example. One image or set of images was shown, and the baboons had to pick images similar to or different from those shown, depending on the test. Using a computer joystick, the baboons had 10 seconds to move a cursor to the appropriate images. When the baboons made a correct choice, they would hear a high musical tone and receive a banana-flavored food pellet.