Rhesus monkeys are aware of the limits of their knowledge, new research shows. Findings suggest evidence of metacognition, long been considered a hallmark of being human, that offers proof that monkeys quickly recognize, on the spot, when a new problem requires information they don't have.

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Rhesus monkeys are aware of the limits of their knowledge, new research shows. Findings suggest evidence of metacognition, long been considered a hallmark of being human, that offers proof that monkeys quickly recognize, on the spot, when a new problem requires information they don't have.