"Monkeys can manage mathematics. Dolphins can be decisive. But US psychologists have broken new ground in the animal intelligence challenge. They have proved that animals are also smart enough to join the "don't-knows".

It means that animals, like humans, may be capable not just of thinking, but of thinking about thinking, of knowing that they don't know. Psychologists call this "metacognition", evidence of sophisticated cognitive self-awareness. Ordinary mortals know it as "dithering"."

Animals 'can think about thought'