WASHINGTON: Baboons are capable of performing complex tasks that involve abstract reasoning, a mental ability that only humans and some chimpanzees were thought to possess, researchers reported on Sunday.

In a series of experiments, researchers at the University of Iowa in Iowa City showed that two baboons could become adept at a task that involved comprehending and identifying abstract relationships between patterns of pictures of objects.

Although the new findings suggest that baboons have more powerful mental abilities than had been thought, the animals are still not believed to be on par with humans or even chimps.

But their ability to perform abstract thinking provides an important clue into how - and whether - language affects the mind’s ability to perform complex tasks of reasoning, researchers said.

In the experiments, researchers showed images on a computer screen to one male and one female baboon. Each image consisted of 16 pictures. The first image depicted 16 different objects, such as a sun, an arrow, a light bulb, a train and a house. The second one depicted 16 identical objects, such as a series of telephones.

The baboons were then shown two new images. One again depicted 16 distinct objects, and the second depicted identical objects. The animals were then asked to pick which of the second two images was most similar to the first image they had seen.

In other words, if they were first shown an image containing 16 different objects, then the right answer would be the second image that also contained 16 different objects.

Adult humans are able to quickly grasp such relationships, but Edward Wasserman, a professor of experimental psychology who helped conduct the research, and his colleagues had to coach the baboons. The scientists sat the animals before a computer monitor as images flashed before them and gave the baboons a reward - a banana pellet, the equivalent of candy for a baboon - every time they made the right choice. After thousands of lessons, the baboons eventually managed to get the answers right about 84 per cent of the time.

But the researchers showed that the animals were not simply repeating by rote a behaviour they had been taught. When the researchers showed the baboons new sets of images that consisted of completely different objects, but followed the same patterns, the animals were still able to spot the abstract similarities and differences, although their success rate dropped to about 70 per cent.

Roger Thompson, professor of biological sciences and psychology at Franklin & Marshall College in Pennsylvania, said that the key to the mystery may lie in language.

Species with linguistic ability have superior abilities to reason abstractly: When small children are given words to describe what they see, their ability on abstract tests improves.—Dawn/LAT-WP News Service (c) The Washington Post.