CHAPTER XXIII

WHY INCREASE THE DENDRITES

After chick and lizard, amphioxus and bird are hatched; after kittens, puppies, and babies are safely born, each continues to grow precisely as it did while it was being developed. That is, every addition to the body of any living creature of any size, from microbe to elephant or whale, is always made by the dividing and the multiplying of individual cells.

This is true of bone and muscle and tendon in every part of the body save one; and the lack in this one. direction makes us catch our breath with surprise and even with alarm.

Scientists tell us that practically all the nerve cells — the neurons that a human being is ever to have, are lodged within him when he is born; and that, although a man may live for a hundred years or longer, and although he may strive throughout each one of these years, the number of his neurons will remain forever the same. Each grows larger, to be sure; axons stretch away from them, long and slender; dendrites may increase; but no amount of wishing or striving or eating or

sleeping will ever give any human being more neurons than he has in the beginning.

This fact makes the outlook rather dismal for those of us who wish to improve our minds; and we turn abruptly to scientists with the question, What then can we do to increase our wisdom and our skill? The answer comes back without a moment's hesitation: Increase your dendrites and connect the neurons.

Further questions bring out further answers, and we end by knowing the following surprising facts.

1. The difference between the power of one brain and another may be nothing more than a difference in the way the neurons are connected with each other.

2. Brain messages run constantly back and forth between different parts of the brain to keep our thoughts from getting disconnected and to keep the messages to our muscles from being confused.

3. These messages must travel from cell to cell, along paths that lie in the dendrites and the axons.

4. To increase intelligence or dexterity in any given direction, increase the number of the paths that connect the neurons which you must use. Brain paths, then, are our only hope-paths within those dendrites and those axons which clasp hands with each other and bind the neurons together. Our task is clear and simple. We must make as many connections

as possible between any set of neurons that govern the special line of thinking or working in which we wish to excel.

But how can we hope to change the number or the power of those slim, twisted fibers that control our destiny? The answer to this question opens a door of hope for each of us.

Persistent practice in any direction develops paths between the neurons which control that particular line of thought or exercise. It is indeed supposed that this practice increases the number of the dendrites themselves.

When you see a boy who is awkward in running and jumping, and a girl who is clumsy in sewing, or cooking, or playing the piano, you have the right to say, “Evidently they are doing the best they can at the present moment, but they have not practiced enough in the past to develop the dendrites that will help them now."

On the other hand, if you see men or women do this thing or that easily, you may say: "I feel like praising them, not for what they are doing now, but for what they have already done; for the faithful practice which has given them this superb system of paths between millions of cells - paths which make it possible for them to do this difficult thing at the present time."

A cousin of mine had been trying all the evening to play hymn tunes on the piano, but she did not succeed. very well and could not understand why she failed. “I

see the notes distinctly," she said, "and I know perfectly where my fingers ought to go; why, then, do I have to fumble so? Why can't I hit the keys?" And I exclaimed :

'Don't blame your present self. You are doing the best you can just now. Blame your past self that didn't practice enough to develop the dendrites with their paths."

There is no question about it. Connections are increased through diligent practice in definite directions.

One man will play the violin easily and brilliantly. Another man, with quite as good a mind and quite as kind a heart, will say: "Thank you, I'd like to do it since you wish me to, but you see my fingers are too stiff. I've hardly ever done any violin practicing. My work has all been on the organ." We therefore blame the man no more for not being able to play the violin than we should blame a baby for not being able to ride a bicycle. We know that the needed neuron connections are lacking for both of them.

Just here it is well to know that even as the bones and muscles of a child grow faster than those of older people, so it is also with the dendrites and the paths in them. Prove this for yourself. Notice how quickly a child learns to ride the bicycle or to dance, to talk a foreign language or to play games. Then notice what slow work an old man makes of these same things. It is for this reason that parents and teachers should give children's neurons a chance while the children are

growing. Connections between different sets of neurons, in any direction whatever, develop fast while a child is young. And those that develop then are capable of doing such good work that they will save him years of time and toil later. For, in those later years, dendrites and paths are slow of growth, and, in certain directions, they do not seem to do as good work even after they are grown.

This is precisely why you "cannot teach old dogs new tricks." It is simply that the dog is old and that it is hard for him to make paths between the neurons. Those which were made in youth, whatever their character, must serve both dog and man in old age. Indeed, it is as true for a puppy and for a child as for a farmer, that any harvest in the summer and fall of life will be measured by the work that was done in the spring.

Clearly enough, there is no such thing as luck in this law of the dendrites. And, quite as clearly, just because luck is cut out, the road to success is open to each one of us. When we are trying hard to learn anything, let our watchword be, "May my dendrites grow; may my brain paths increase." Any boy who follows this inspiration may turn himself into the man he wishes to be. Any girl may become her own model. Neither dares to trust to luck, for both know that, from the time the first stimulus went across the first amoeba until now, no accident has ever built up a fine set of brain paths.