I want to know how people think. I am particularly interested in “high-level cognition,” such as how people understand whole stories, and solve complex problems. I particularly want to know how the brain thinks. All research on the brain and on thinking or perceiving, without regard to the brain, is interesting and useful. But I find it particularly satisfying to try to link the brain’s wetware to the mind’s software. Not just for the sake of connecting the mental realm to the physical, but because evidence from each domain helps constrain theories in the other, hopefully providing novel insights into both.
One area of interest is creative cognition. In particular, one type of creative cognition is exemplified by "insight" solutions to problems. These are the solutions that are accompanied by "Aha" or "Eureka" experiences. It's as if a light turns on and you suddenly see an answer to a problem that had stumped you. Sometimes this happens when you didn't even know you were thinking about the problem. A series of behavioral and neuroimaging experiments has begun to de-mystify this process, and reveal <a href="http://groups.psych.northwestern.edu/mbeeman/PLoS_Supp.htm" rel="nofollow">how the brain produces insight.</a>
Another line of research investigates how people "fill in the gaps" when understanding stories and complex discourse. Consider what happens when you hear:
"Mary bought a big package of white paper, then headed off to her cabin. A month later, she gave her husband a new novel."
You probably inferred that Mary wrote the novel. People seem to make inferences like this effortlessly. But clearly, some cognitive – and neural – effort is required. This is reflected in subtle changes in fMRI signal observed while subjects listen to stories that either imply an event – like the passage above – or explicitly state it.
<strong>Two brains are better than one</strong>
One approach I've taken is to examine differences in the way the <a href="http://www.nuin.northwestern.edu/wp-content/uploads/2012/01/TiCS_BAIS_lang1.pdf" rel="nofollow">right and left hemispheres process information, particular in regards to language</a> and problem solving.
Studying hemispheric differences has tremendous potential to reveal critical components of higher level processing, because the two hemispheres share similar gross structure and input and output pathways, yet differ in cognitive processing. A particularly interesting area to study is language processing, for which the left hemisphere has long been thought to be "dominant." Recent empirical and theoretical work suggest that, although the Left hemisphere is better at many straightforward language tasks, both hemispheres process linguistic information, mostly in parallel, at all levels of processing, each computing the input in a unique way, and each contributing to understanding.
I've proposed that semantic information is represented and processed through the summed distributed activity of many thousands of neurons divided over both hemispheres (see, e.g., Beeman, 1998; Beeman et al. 1994). When processing words, the right hemisphere weakly activates large <strong>"semantic fields"</strong> of related information, including information only distantly related to the input words. This <strong>relatively coarse semantic coding</strong> accounts for the right hemisphere's linguistic inferiority, as well as its sensitivity to semantic overlap from distantly related words and its subtle contributions to discourse comprehension. In contrast, the left hemisphere strongly activates a narrow semantic field of closely related information. This <strong>relatively fine semantic coding</strong> accounts for left hemisphere linguistic superiority, as well as its relative insensitivity to distant semantic relations and vulnerability to misinterpretation in certain discourse and problem solving contexts.