R-mode Sees Forest; L-mode Sees Trees
Pattern matching is a key ability demonstrated by experts. It’s how they can narrow their choices and focus on just the relevant parts of a problem.
And for the most part, the pattern matching we’ve been interested in lies in the neglected R-mode activity. But both L-mode and R-mode have their separate approaches to pattern matching, and in the end you need both.
Consider the following figure:[46]
| | I I |
| | I I |
| | I I |
| | I I |
| | I I I I I I I |
| | I I |
| | I I |
| | I I |
| | I I |
Here we have an H character made up of individual I characters. This kind of pattern is known as a hierarchical letter. Psychologists present this sort of figure to subjects one eye at a time—quickly—and ask them to identify the big and small letters.
The hemispheres in your brain tackle this problem of identification differently; one hemisphere is better at identifying the local criteria (the small letters), and the other is better at the global criteria (the big letter).
Subjects do very well when asked about the global pattern using their left eye, which uses mostly R-mode. They also do very well when asked about the local criteria (the parts) using their right eye, which uses mostly L-mode. But when asked the other way around, the results are considerably poorer. There looks to be some significant lateral specialization going on here.
This experiment seems to amplify the fact that if you’re looking for global, holistic patterns, you need R-mode. If you need to analyze parts and look into the detail, then you need a more L-mode approach. For most of us, this level of specialization is how it is. R-mode sees the forest; L-mode sees the trees.
But for some fortunate few, the hemispheric differences are not as profound. Math prodigies, in particular, do not show these differences; their brain parts are much more cooperative.[47] When they see the I characters or the Hs, both hemispheres are more equally involved.
If by chance you aren’t a math prodigy, then we need to take a look at some other way to get the R-mode and L-mode to cooperate: to better integrate L-mode and R-mode processing. We’ll take a look at how to do that in the next chapter.