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September 11, 2007
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Rats can reflect on their knowledge, study finds
March 8, 2007
Courtesy University of Georgia
and World Science staff
Let’s say a college student enters a classroom to take a test. She probably already has an idea how she will do—knowledge available before she actually takes out a pencil. But do animals have the same ability to think about what they know or don’t know? Courtesy
University of Georgia
A new study has found that laboratory rats do. It’s the first to show that any
non-primate has this gift, and could lead to deeper studies on how animals and humans
think, the investigators said.
“This kind of research may change how we think about cognition and memory in animals,” said one of the scientists, psychologist
Jonathon Crystal of the University of Georgia in Athens, Ga. The findings appear in the current issue of the research journal
Current Biology.
Scientists have believed for some time that people and non-human primates are capable of
“metacognition”—reasoning or thinking about one’s own thinking.
Whether other animals do it has been unclear. Bird studies produced inconclusive results, according to Crystal and
his co-author, Allison Foote, a graduate student at the school. The
pair called their work the first to find metacognition in a non-primate, a proposal that may well be controversial.
The experiments involved a “duration-discrimination” test: offering rats rewards for classifying a brief tone as either short or long. A right answer led to a large food reward; a wrong one, no prize. Also, on some tests runs, before starting, the rats were given a chance to
back out of the test, in which case they got a small reward anyway.
Some of the test choices were easy: the signal lengths were very different. Other choices were hard, as the difference was smaller. In these cases the rodents faced a dilemma: Should they take a chance
on the test and risk no reward? Or should they bail out and take the small, but guaranteed prize?
If rats know whether they know the answer, Crystal said, they’d presumably decline most often on harder tests. They would also perform worst on hard tests that they’re not given an option to decline. “Our data showed both to be true, suggesting the rats have knowledge of their own cognitive states.”
So “the rats know when they don’t know the answer,” and responded accordingly, said Crystal. The results present a rodent model that should allow researchers to understand better what animals are “cognitively sophisticated” and why, according to the researchers.
The research will also open new lines of inquiry into the brain mechanisms underlying this ability, they added. Reflecting on one’s own mental life is thought to be a defining feature of humans, but the finding of metacognition in rats would suggest this may be widespread among animals, the investigators speculated. Does it mean, for example, that rats are “conscious,” and could that also be true of other non-primates? Future research could clarify that, Crystal and
Foote said.
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Let’s say a college student enters a classroom to take a test. She probably already has an idea how she will do—knowledge available before she actually takes out a pencil. But do animals have the same ability to think about what they know or don’t know? A new study has found that laboratory rats do. It’s the first to show that any non-primate knows when it doesn’t know something, the invest igators said, and could lead to deeper studies about how animals and humans think. “This kind of research may change how we think about cognition and memory in animals,” said one of the scientists, psychologist Jonathon Crystal of the University of Georgia in Athens, Ga. The findings appear in the current issue of the research journal Current Biology. Scientists have believed for some time that people and non-human primates are capable of “metacognition”—reasoning or thinking about one’s own thinking. Whether other animals do it was unclear; studies on birds produced inconclusive results, according to Crystal and colleagues. They touted their work as the first to find metacognition in a non-primate, a proposal that may well be controversial. The experiments involved a “duration-discrimination” test: offering rats rewards for classifying a brief tone as either short or long. A right answer led to a large food reward; a wrong one, no prize. Also, on some tests runs, before starting, the rats were given a chance to decline the test completely, in which case they got a small reward anyway. Some of the test choices were easy: the signal lengths were very different. Other choices were hard, as the difference was smaller. In these cases the rodents faced a dilemma: Should they take a chance on the test with the risk of no reward? Or should they bail out and take the small, but guaranteed prize? If rats know whether they know the answer, Crystal said, they’d presumably decline most often on harder tests. They would also perform worst on hard tests that they’re not given an option to decline, he added. “Our data showed both to be true, suggesting the rats have knowledge of their own cognitive states.” So “the rats know when they don’t know the answer,” and responded accordingly, said Crystal. The results present a rodent model that should allow researchers to understand better what animals are “cognitively sophisticated” and why, according to the researchers. The research will also open new lines of inquiry into the brain mechanisms underlying this ability, they added. Reflecting on one’s own mental life is thought to be a defining feature of humans, but the finding of metacognition in rats would suggest this may be widespread among animals, the invest igators speculated. Does it mean, for example, that rats are “conscious,” and could that also be true of other non-primates? Future research could clarify that, according to Crystal and colleagues.