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Rats understand cause and effect, researchers find
Feb. 16,
2006
Special to World Science
Rats may understand cause and effect, contrary to widespread belief among scientists, a study has found.
It’s well known that animals can quickly learn that events are connected in some way. They can learn, for instance, that one event usually follows another. But creatures aren’t generally thought to reason that the second event could happen because of the
first.
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Courtesy National Institutes of Health
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But that assumption may be wrong, according to the researchers who
conducted the study.
The scientists, Aaron Blaisdell of the University of California-Los Angeles and colleagues, repeatedly showed rats a light followed by a tone.
Then, if the tone was played alone, the
rodents started to behave as though the light must also have gone on. But when rats produced the tone themselves—by pressing a lever—they didn’t act as though the light must have flashed, the researchers reported.
The rats’ reasoning was like our ability to understand that it hasn’t just rained when we see a wet lawn we just watered with a hose, according to the scientists.
They said they could ascertain the rats’ reasoning processes to some extent because when the light flashed, the rats were also given some food along with the sound. The rats learned to start looking for food after the light was flashed. But they didn’t do this as much when they themselves had set off the tone.
“A number of researchers have recently concluded that causal reasoning is a faculty that divides humans from animals,” the researchers wrote in the Feb. 17 issue of the research journal
Science, where they reported their findings. “The present results cast doubt on that conclusion.”
The rats might not understand the detailed physical mechanisms underlying cause and effect, Blaisdell and colleagues added. Nonetheless,
they argued, the rodents show a key component of causal reasoning: they “grasp the relationship between seeing and doing,” and how these influence events differently.
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