Macaques shown to perform simple addition

Science : Further insight into how the human brain may process numbers has been shown through a recent experiment with rhesus macaque monkeys. Margaret Livingstone of Harvard Medical School and colleagues taught several macaques not only how to distinguish between single-digit numbers and determine which of two numbers is the larger but also how to add two numbers together and compare that value with another number to determine which is larger. While the researchers altered the experiment in various ways to rule out the possibility that the monkeys were simply memorizing all the combinations rather than performing actual math, they did notice that the monkeys tended to underestimate a sum. Given the choice of which is larger, the number 13 or the sum of 6 and 8, they chose 13. The researchers say the monkeys appear to be focusing on the larger of the two numbers in a sum and paying less attention to the second value. Such research could further the understanding of how humans process numbers and lead to ways to overcome certain learning disabilities.