This is your brain on nouns
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Even as a young man, my father always had lots of words that stood in for nouns he couldn’t call to mind when he needed them. ‘Hand me that whatchamacallit,’ he’d say, pointing to the hammer just beyond his reach. ‘Oh, I left my keys on the whosamajigee,’ he’d say, and we usually knew to check on top of the dresser in his bedroom.
I do it myself sometimes, and my kids aren’t nearly as understanding as my siblings and I were with my dad’s absent-mindedness.
Thank goodness, then, that brain imaging research has progressed to the point where researchers can detect regularities in the activation of the human brain when we ponder such words as ‘hammer’ and ‘dresser.’ I guess in a pinch, my kids could always order up a functional Magnetic Resonance Image (or fMRI) of my brain and get a translation if they can’t figure out what a ‘whosamawhatchit’ is on their own.
At Carnegie Mellon University, Marcel Just and his colleagues have done just that, and have described it in an intriguing article in the journal PLoS One out on Tuesday. Just, a psychology professor and director of the Center for Cognitive Brain Imaging at Carnegie Mellon, tried to pinpoint what our brains do when we think of the words that represent commonplace items--building parts such as door, window and chimney, body parts such as arm, leg and eye, different types of tools, vehicles, vegetables, animals or pieces of clothing.
Just and his colleagues put 11 right-handed volunteers into an fMRI machine and had them read a list of 60 commonplace nouns six times over in varying random order, taking a moment to reflect upon each. As the subjects did so, the researchers documented the precise coordinates of the brain’s activity in response. They sifted out the brain activity that was common to all the words--say, activation of visual processing areas that play a central role in reading--and looked for patterns of varying brain activation that would reveal regularities in the way we ‘think’ about common things.
Not surprisingly, thinking about a single noun like ‘truck’ or ‘butterfly’ sparked activity in many different places in the brain. That’s just more evidence that the brain is a far-flung network of regions and specialized cells that exchange information and coordinate efforts in even the simplest task. But four dominant patterns of brain activation seemed to emerge--clusters of brain activity that were so regular, Just and his colleagues were later able to identify what word a subject was pondering just by looking at its ‘fMRI activation signature.’
Those activation patterns suggested that subjects were sorting commonplace nouns into four lines: things that are manipulated; things that are eaten; things that represent shelter, or an entryway into shelter; and finally, words that are long. Some of the brain regions lighted up when a ‘manipulation’ noun was read were areas that typically activate when we imagine grasping something. When a ‘shelter’ noun was read, brain areas that have been associated in past research with looking at, recognizing and identifying buildings and structures became activated. ‘Eating’ nouns typically energized a region of the brain associated with the coordination and movement of the lower facial muscles.
What’s more, Just and colleagues showed that when it comes to thinking about everyday objects, we don’t each have unique patterns of brain activation: On the whole, the regular patterns of brain activation that distinguished, say, ‘arm’ from ‘airplane,’ or ‘telephone’ from ‘shirt’ were similar across all 11 subjects.
This study isn’t easy reading: It has, for instance, equations that elicited a sudden blank in brain activity for me. But for people who like to think about how we think and how we process human language in all its complexity, it’s really cool stuff.
-- Melissa Healy