"We set out to find out how animals conceive the world around them," said Dr. Amanda Seed, a lecturer at the University's School of Psychology & Neuroscience. ""Do they have any idea that objects have abstract properties, like solidity and weight? Or do they rely on learning arbitrary relationships between what you see, what you do and what you get, in the same way that we learn to stop at a red light?"
The scientists presented capuchin monkeys, bonobos and chimpanzees with a puzzle: each individual was given a box containing two pieces of string. One string connected to a food reward and could be pulled to bring the food to the subject. The other string was connected to food but was cut in the middle.
There were two variations of the puzzle: one where the box was covered but had a representation of the strings on the top of it; and one in which the box was uncovered and the strings attached to food were fully visible.
The team found that the subjects performed better when presented with the uncovered box and the visible strings - the puzzle that most "made sense." Seeing the string connected to the food itself was easier to understand. The researchers said that the monkeys and apes could solve the puzzle when they could see the function of the object (the string pulling on the food) - similar to the way that kindergartners behaved when they were given the same puzzle.