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The Story of the Lateralized Brain May 13, 2009

Posted by Nina Rosenstand in Animal Intelligence, Nina Rosenstand's Posts, Science.

Weren’t we taught that (1) you’re either “left-brained” or “right-brained”? And weren’t we taught that (2) only humans have lateralized brains, i.e., brains that are divided into two asymmetrical brain hemispheres? Turned out we were lied to. Or (since I have a problem with accusing people of lying if they were just wrong) our teachers were misinformed. But now we hear (Zimmer, “The Big Similarities”)  that other animals also have lateralized brains—something that those of us with pets have suspected for a long time. And why not? From bees to birds to mammals, our brains are specialized in right- and left brain structures, which may aid the individual in developing fresh survival strategies. And the “right-brained” and “left-brained” story has always been oversimplified; of course we all make use of all our brain, even if we have different talents (and the pop slogan that “We only use 10 percent of our brain” should be taken out and beaten to death). And we have known for a while that, as separate as the brain halves may look, the corpus callosum that unites them (which is thicker in female brains than in the male equivalents—so make of that what you will) is important for creating a unified conscious experience. So, if anyone is still in doubt, yes, we have animal brains. Some little critter a long time ago survived because it had a lateralized brain, and we have inherited it. But of course that doesn’t mean we haven’t improved on the first model, and the next, and the next, and made it into a uniquely human version. Zimmer’s article doesn’t much go into that, but there’s no shortage of research in that area.

What I’m curious about right now is our story-telling capacity. It resides in the left brain hemisphere, with our processing of words, but language is also processed in the right hemisphere, for its emotional content. We don’t tell stories without emotional values—otherwise it would be like reading from the phone book.  So the good storytellers among us have a vivid cooperation between the two hemispheres. But how about non-human brains? Those big mammal brains that recognize faces, produce and understand meaningful sounds, communicate with body language, have strong emotional ties to their group, and remember where they buried last year’s bones? If future researchers  were to find that those same brain areas also light up when scanned, maybe we should start looking for a grammar of nonhuman animal communications…and maybe some day I’ll have to stop saying that the ultimate human characteristic is that we are the ones who tell stories…



1. thyroidinfo - May 13, 2009

My daughter was born with Agenesis of the Corpus Callosum. She can tell intricate stories, but she is incapable of lying….go figure!!

2. Paul Moloney - May 14, 2009

There could be a good case made in at least tending to think that some people are lying when they make a mistake. The lie is not in the mistake itself but in the pretentiousness of the person that makes it. The pretentious person claims to know more than they do, which is a form of lying. The lie is the cause of the mistake. The pretentious person also claims that others know less than they do, which is an insult to intelligent people.

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