A new study on a troop of zoo baboons has shown that even monkeys can understand numbers, and that this numerical ability is innate and not a learnt one. The study challenges the idea that only humans have a concept of mathematics.
The research was conducted by Jessica Cantlon from University of Rochester and her colleagues. In the study, researchers monitored eight olive baboons that were between 4 and 14 years of age.
These monkeys were then given about 53 tests to understand their numerical abilities. In one such experiment, researchers placed a varying number of peanuts in different cups. The baboons received all the peanuts in the cup, regardless of the quantity.
Over time, researchers found that baboons picked up the cup with the largest number of peanuts. When the ratio of the peanuts was difficult to determine (such as 5 and 6), the baboons were able to pick the cup with the most number of peanuts with 55 percent accuracy.
Authors concluded that baboons use the analog system or the "more than" or "less than" cognitive approach while making a decision about the number of peanuts. Children who haven't learnt counting and adults who have to make quick decisions on quantity also rely on this system.
"The human capacity for complex symbolic math is clearly unique to our species. But where did this numeric prowess come from? In this study we've shown that non-human primates also possess basic quantitative abilities. In fact, non-human primates can be as accurate at discriminating between different quantities as a human child," said Jessica Cantlon, assistant professor of brain and cognitive sciences at the University of Rochester and co-author of the study, said in a news release.
Previous studies on other animals and birds have shown that they too possess some ability to understand quantity, but many of these study results are slightly biased, as the animals are extensively trained. In some cases, like that of a horse, the animal could make a decision based on the subtle body language of the trainer rather than based on its own aptitude for math. In the present study, researchers conducted trials on untrained animals and used two experimenters for each trial.
Researchers then tested numerical abilities of two baboons in over 100 trials and found little improvement in their test scores, indicating that the ability of the monkeys wasn't learnt.
The study is published in the journal Frontiers in Psychology.