I made a big deal about the limits to our knowledge of what we don’t know in Incognita Incognita. Reality check: even rats understand the limits of their knowledge, so I shouldn’t get too carried away.
In The Rodent Who Knew Too Much in ScienceNOW (8 Mar 2007, subscription required), Gisela Telis reports on a study that tested the self-knowledge of rats. The experimenters trained rats to understand that they could get a big food reward (six pellets) if they correctly distinguished a long sound from a short one. They could boycott the test if they wanted to, though, and go for a smaller but guaranteed reward (three pellets). As the sounds became harder to distinguish, the rats would opt out and go for the certain, though less generous, reward.
The ability to gauge one’s own knowledge is known as metacognition. We know that humans can do it, and it’s been demonstrated in monkeys and dolphins; this is the first time the effect has been shown in smaller-brained animals.
Metacognition, or “thinking about thinking,” is a strategic activity. It allows us to reflect on a (tactical) cognitive lack, such as having a blind spot for taking immediate steps to remember the name of someone you’re introduced to. (“A pleasure to meet you, John. So tell me, John, did you enjoy the lecture? You know, I agree with that assessment, John.”) Metacognitive strategies can be learned – which gives me hope that any conclusions I might draw about Hard Intangibles will lead to more effective thinking.
P.S. Latin doesn’t seem to distinguish between "rat" and "mouse" (mus). Gnarus means "knowing" or "expert."