Test suggests baboons can reason

A pair of trained baboons show some signs of abstract thought, a new study suggests, potentially putting the monkeys in the same category as chimpanzees and humans.

Finding the ability to reason in a non-ape primate such as the baboon raises new questions about the evolution of intelligence.

Baboons belong to a group called the old world monkeys, which split off from the group that gave rise to apes and humans about 30 million years ago.

Scientists at the Centre for Research in Cognitive Neuroscience in Marseille, France and the University of Iowa conducted the study, which appears in this month's issue of the Journal of Experimental Psychology.

The two baboons were given tests to determine if they could pick out groups of objects that were "the same, but different."

They were first shown a set of 16 simple images such as a sun, a light bulb, a house, a telephone on a computer screen. The images were either all the same or all different.

The baboons were then shown two new sets of 16 images, one with 16 different images and one with 16 copies of one image. The baboons could select one of the sets of images with a joystick.

If the first set of images were all the same say, all trains and the baboon picked the set of images that were also all the same say, all clocks it was given a banana-flavoured pellet.

If the first set of images were all different, and the baboon selected the set of images that were also all different, it was also rewarded.

It did take a while for the baboons to get the hang of the test; only after several thousand tries were the baboons able to get the right answer 80 per cent of the time.

Two people who took the test, on the other hand, could master the test after only 100 tries.

But the researchers say the baboons are nonetheless capable of some analogical thinking (as in, A is to B as C is to D), which psychologists believe is the basis for reasoning.