Brain Rule #3: Wiring

In this next installment of my discussion of Dr. John Medina's fabulous book Brain Rules, we'll take a look at how and why every brain is unique. Dr. Medina's rule is "Every brain is wired differently."

You can imagine the brain as a huge intercontinental road map, with millions (billions?) of pathways for transmitting information. There are tiny back roads where hardly anyone ever goes, city streets and two-lane highways, and massive interstate freeways. The larger routes don't just accommodate more traffic, they also have a higher speed limit - allowing messages to travel more rapidly along them. Information routes in the brain become larger and faster the more they are used, so the skills and knowledge that you use regularly have the fastest and strongest connections in the brain.

The interesting thing is that no two brain maps are the same. Although the major highways are in more or less the same places from person to person, the smaller routes differ, and the smallest ones can be totally unique to each person. Everyone's brain map is distinctly their own.

Whenever a person learns something new, he or she forges a new pathway in the brain. Neurons split and make a new connection. The brain changes; it rewires itself. The new pathway is negligible at first - like a few footprints in the grass - but if it is used repeatedly, it will become larger, deeper, and faster. In this aspect, the brain acts like a muscle: the more activity you do, the larger and more complex it can become. So repetition is as central to learning as it is to weight lifting. Learners need to repeat, repeat, repeat in order to lay down strong pathways in the brain.

This process of forging new pathways and then strengthening them is what teaching and learning are all about. When we teach our learners something new, and then help them master it through meaningful repetition, we are helping them rewrite the road map of their brains.

Because every brain is wired in a unique pattern, each learner's needs are also unique. Everyone learns at a different pace and has different associations and networks in the brain to build on, and thus will master complex material to a different depth in a given period of time. Even if every learner starts out in roughly the same place at the beginning of a lesson (which is itself unlikely), they will not end up in the same place by the end of the lesson. There is no such thing as a homogeneous classroom.

So what does this tell us? For one thing, class sizes really do matter. Since each learner is unique, one of the teacher's most important responsibilities is keeping track of where each learner is at. This is much easier to do when there are fewer people to keep track of! In order to perform well at this job, a teacher must be highly adept with Theory of Mind skills (which we learned about in the last chapter). That's because a teacher relies on the subtle mental and emotional signals being broadcast by the learners to "get a feel" for who understands what, who's frustrated, who's confused, who's made a good analogy, who's got a mistaken understanding, who's off-task, who's bored, who's excited, etc. In a crowded classroom, too many signals get lost, and the teacher runs the risk of losing students - the proverbial problem of people "falling through the cracks". In a classroom with fewer learners, the teacher can more easily pick up on signals from everyone and make sure she is keeping everyone on track.

One other thing this tells us is that differentiated or customized instruction is not only beneficial but may in fact be necessary if we are to achieve high quality outcomes for learners. One way this might be done is through software programs that can diagnose the gaps in a particular learner's knowledge and then guide the learner to improve in those areas. This has been done with reading skills software and has proven very effective. Students in a class all get the same lesson from the reading teacher, but then also have a chance to work independently on computers. The computers have adaptive software that assesses their reading skills and then targets their areas of weakness. The difficulty of course, is in developing high quality, engaging, educational adaptive software. It's not that it can't be done - it just that it's going to cost money and time: two things educators never seem to have enough of.