Years ago I watched a documentary that was about how humans are unique compared to other animals. In it they highlighted an experiment that was done on both human toddlers and chimpanzees. The experiment involved giving the subject (baby or chimp) a wooden block, if they set the block up on its side they would be rewarded with a grape. After they were trained to expect a grape every time they set the block up, the block was replaced with a different block which was slanted on its sides and impossible to set upright. The result was that all of the chimps would keep trying and failing to set the block upright and would eventually get frustrated and throw the block away or storm off, whereas the babies would try and fail and then pick the block up and look at to try to see what had changed.
Does anyone know what this experiment is called or the name of the documentary that talked about it?