How People Learn: Synapse Building For Rats (And Humans)

Continuing in my summer book study...

In the book How People Learn, the chapter on "Mind and Brain" is heavy on neuroscience, starting with the essential process of synapse development.  Our synapses are connections between neurons, and substantial research shows that learning occurs through synapse development.  Much of the chapter is about studies of what does and does not produce rich synaptic development in lab animals.

One group of rats was taught to traverse an elevated obstacle course; these "acrobats" became very good at the task over a month or so of practice.  A second group of "mandatory exercisers" was put on a treadmill once a day, where they ran for 30 minutes, rested for 10 minutes, then ran another 30 minutes.  A third group of "voluntary exercisers" had free access to an activity wheel attached directly to their cage, which they used often.  A control group of "cage potato" rats had no exercise.

Researchers then examined the rats' brains, looking both for blood vessel development and for synapses per neuron, and found that both sets of exercisers had higher density of blood vessels than the acrobats and cage potatoes, but

But when the number of synapses per nerve sell was measured, the acrobats were the standout group.  Learning adds synapses; exercise does not.

What struck me in this was something I'm not sure the the authors meant me to notice: I heard the word "exercise" in its classroom context, as meaning an activity assigned by the teacher, often with repetitions and an emphasis on speed, like spelling lists and sets of arithmetic problems.

I wonder how many of our teaching traditions reflect the idea that the brain is like a muscle and will build through steady repetition that truly resembles physical exercise.

More than that,  I wonder how much we will need to change if we want learning that happens as developing sets of synaptic connections.  That understanding suggests that the some of the most important work comes in the opportunities to "put things together " and "see how it all connects."

It seems likely that learning of that kind will require fewer drills and more exploration, fewer lists and more reasoning about how different elements relate, fewer details and more depth on key organizing concepts than we have expected in the past.  That does not have to  mean no drills, no lists, and no details.  It does mean realizing that exploration, reasoning, and organizing concepts must be given a rich share of the time and energy students bring to their learning.  And it does mean that the number of drills, lists, and required details has to be restrained to allow the richer elements opportunity to occur.