Tools of engagement: Information seeking in chimpanzees.

Two widely studied and impressive cognitive feats in nonhuman animals, metacognition and tool use, both require the cognitive tools of monitoring and controlling knowledge states and adaptive actions toward desirable outcomes. In a recent study, Perdue, Evans, and Beran (PLoS ONE, 13(4), e0193229, 2018) found that some chimpanzees used tools to selectively acquire information and make inferences, indicating metacognitive awareness and appropriate use of tools depending on the content of those knowledge states.