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What do first graders and baboons have in common? According to new research, both can tell the difference between written words and random sequences of letters.
As NPR's Jon Hamilton reports, the finding challenges some conventional ideas about what goes on in the human brain when we read.
JON HAMILTON, BYLINE: Scientists have assumed that reading relies on the same brain circuits involved in spoken language. Now they're considering a more complicated explanation thanks to six baboons who took part in an unusual experiment.
The baboons live in the south of France and they spend their time in an enclosure that includes nine testing booths. Jonathan Grainger of Aix-Marseille University says that baboons, like first graders, can be motivated by food and video games. So he put treats and touch-screen computers in the testing booths.
JONATHAN GRAINGER: And they just go up and do an experiment, you know, whenever they want, basically. There's no stress to the animal. They're doing this because they want to.
HAMILTON: Grainger says all the baboons had to do was step into a booth and tap the screen.
GRAINGER: First thing that comes up is a string of four letters which, at random, could be a real English word or what we call a non-word, a string of letters that's not a real English word.
HAMILTON: Then the baboons had to indicate whether they were looking at a word, like K-I-T-E, or a non-word, like E-K-T-I. After doing this thousands of times, all the baboons learned to recognize at least 80 words, even though they had no idea what the words meant. And Grainger says a baboon named Dan learned more than 300 words.
GRAINGER: Yeah. Dan's our star baboon. He's a high performing individual, basically. He does well in most tasks.
HAMILTON: But here's the amazing thing. Dan and the other baboons also learned to tell whether a string of letters they'd never seen before was an English word. That's something first graders learn to do when they start reading, but scientists had assumed that kids were simply sounding out the letters to decide whether they made sense. And, of course, the baboons couldn't do this because they're not learning to read a language they already speak. They had to rely on a part of the brain that can tell whether objects fit a known pattern.
And here's where the experimenters started learning from the baboons. Grainger says his team realized that when people see a word they're probably doing the same thing as their primate cousins.
GRAINGER: The part of the brain that we use to recognize words when we're reading is actually a part of the more general brain region for visual object identification.
HAMILTON: Grainger says brain scans of people reading support that notion, though, of course, we also use language areas to understand what we're reading.
Michael Platt, who directs the Duke Institute for Brain Sciences, says he was surprised by what the baboons were able to do.
MICHAEL PLATT: I was really looking for holes to poke in this study, but it was very difficult to find any because it was really beautifully done and I think the lynchpin here is the fact that the baboons, once they had learned the rule, could generalize to new words that they had not seen before.
HAMILTON: Platt says, when you think about it, the finding makes sense given what's known about human and animal brains.
PLATT: Brains are always looking for patterns. They're always looking to make some statistical pattern analysis of the features and events that are in the environment and this would just be one of those.
HAMILTON: Platt says that's a big departure from the idea that reading is a direct extension of spoken language.
PLATT: It's a very different way of thinking about what reading and writing really are and it could have some implications, for example, for thinking about how we might improve education in reading and writing for young children.
HAMILTON: Take kids with dyslexia. The baboon study suggests their problem might be in parts of the brain that identify objects, not the ones that process language. The new research appears in the Journal of Science.
Jon Hamilton, NPR News.