14 DAY TRIAL // Researchers have been surprised to learn in a new study of another trait of intelligence chimpanzees display, one that was never encountered before. They have noticed that the primates are perfectly capable of recognizing precisely how big a pint of liquid is. The animals can also tell the volume of any other measure. The finding tops previous investigations, which have shown that chimps can distinguish between discrete quantities, such as telling a lower number of treats from a higher one. The new discovery essentially indicates that the species has a primary understanding of the physics of liquids, which is something completely remarkable, the BBC News reports.
The primates were found to be capable of separating between a pint that was half full and one that was entirely filled. Details of the study and the conclusions scientists arrived at can be found in the latest issue of the esteemed scientific publication Animal Cognition. The study comes from researchers based in the United States, at the Georgia State University, in Atlanta. The team leader, comparative psychologist Dr. Michael Beran, has spent more than ten years looking into the mental abilities of apes, monkeys and humans. He is one of the researchers who first demonstrated that primates were capable of simple adding and subtraction calculations.
But liquids are different from discrete quantities. While the primates were able to identify between five or eight or ten candies, the researchers were curious whether they could keep track of the amounts of liquid in a glass. This is very important because liquids form a continuous quantity, which progressively gets larger as more of the stuff is added. “So I wanted to know whether they would perform as well when they had to judge two poured amounts of juice,” Dr. Beran explains. He set up some experiments in which chimps had to watch experts pour liquid with a syringe in a transparent, and an opaque container, respectively.
In instances when liquid was poured into opaque glasses, the chimps demonstrated that they could mentally visualize how much juice was being poured in the container, in spite of not being able to see the level in the measuring cup themselves. “They had to watch juice pour into containers and once the juice was there, it was out of sight. So they had to remember how much juice is there, just from seeing it fall,” Dr. Beran explains for the British news agency.
“I have no doubt such skills would prove valuable in the wild. Chimpanzees make many decisions regarding how to spend their time foraging, and where to forage, and also they must attend to who else is around them in terms of the number of individuals. In many of these cases, quantity offers valuable information, and so sensitivity to quantity and the ability to judge quantities and use forms of mental accounting would be adaptive,” the expert concludes.