Chimpanzees and orangutans look for information to fill gaps in their knowledge

It's a familiar problem: you leave the house and while closing the door, the question whether the stove was turned on or off pops up in your head. Although annoying, this problem could easily be solved by turning around and taking a second look. This simple example illustrates an important form of thinking: metacognition or the ability to monitor ones' own mental states. Before turning around, you assess whether you remember the state of the stove. Once you realize that you don't remember, you seek additional information. Importantly, in humans, this monitoring process is very flexible and can be applied to all sorts of thoughts, not just the ones about your stove. Researchers from the Max Planck Institute for Evolutionary Anthropology and the University of St. Andrews asked what great apes would do when they are confronted with such a situation.