Paper presented at the “Brain Development in Young Children: New Frontiers for Research, Policy and Practice” Conference, Chicago, on June 13, 1996

Why are IQ levels rising throughout the developed world? In the U.S., for instance, the average IQ has climbed 24 points since 1918. Similar increases were registered in other countries.

We like to think of ourselves as the top of the line, the epitome of a long lineage of human beings. But we still have a lot to learn about our brains and our bodies.

Not too long ago breaking the four minute mile was thought to be impossible. But once that barrier was breached by Roger Bannister in 1954, it set the stage for the rise of the superathlete. Today runners routinely run a mile in less than four minutes and every Olympics sees old records smashed.

A similar phenomenon is happening to the brain. Not too long ago the brain was considered to be hard-wired. For the most part, people were not concerned about the development of a child’s brain until he or she went off to school.

Scientists are finding that this notion is as much of a myth as the unbreakable four-minute mile. There is a growing recognition today that the kind of experiences the brain is exposed to in the first three years dramatically influence how it operates–for the rest of its life.

Some revolutions are obvious because they are fought with weapons. Others, especially those that require new ways of thinking, tend to sneak up on us. The revolution in brain research is only now revealing itself. For the past 5-to-10 years scientists have been busy figuring out how the brain gets built, how it gets damaged and how it can be repaired.

At the core of this new knowledge is the plasticity factor, a term that scientists use to describe the brain’s amazing ability to constantly change its structure and function in response to experiences coming in from the outside. They recently discovered chemical lifesavers inside the brain called neurotrophic factors, which are critical for the development and maintenance of brain cells. Scientists are searching for ways to replenish these vital chemicals when they decline with age.

With the growing understanding of how the brain works comes the opportunity to increase brain power. Who wouldn’t want to improve their memory, stop forgetfulness and prevent Alzheimer’s disease and other neurodegenerative disorders. For me this is the best time to be a science writer, because the powerful new tools of molecular biology and genetic engineering are revolutionizing most fields.

Look what’s happened to cancer. Ten or so years ago cancer was thought to be more than 100 different diseases and scientists didn’t think they would ever understand it. But, using molecular biology’s new tools, they have solved cancer’s mystery. Cancer is a derangement of normal genes. In a sense, we all carry the seeds of our own cancers in our genetic codes.

How does that happen? Genes that promote cell division can cause cancer when they forget to turn off. They are like accelerators stuck to the floor. But cancers can also result when the brakes fail, as when genes that are supposed to regulate cell division fall asleep on the job.

Turning those same tools loose in neuroscience is producing a similar revolution. Scientists have learned more about the brain in the past 5 years than in the last 100. The explosion of new knowledge has led scientists to a greater understanding of the brain’s biology and to finding potential causes of violence. What we thought we knew about the relationship between a deprived or bad upbringing and the increased risk of criminal behavior is now being traced to the brain’s chemistry. It is the biological smoking gun of violence. We are now finding the molecular answers to the things that happen to the brain that we could only grope for with older techniques – such as psychology, psychiatry, and sociology.

Now we can see thoughts with new imaging devices that can spy on the living, working brain, and we can eavesdrop on individual brain cells to listen to their chatter. With this new technology we can begin to understand through genes, chemistry and experience the sayings, which were based only on observation, “the child is father to the man” and “as the twig is bent, so grows the tree.” It also is evident now why a child can easily learn a new language in a foreign country, if he or she does so at the age when the brain cells that process language are being wired.

And this new knowledge puts to rest the old, contrived argument of which is more important, nature or nurture, genes or environment. Do we come into the world fully programmed to act the way we do or are we blank slates waiting to be written upon? The answer is that genes and environment are probably equally important. The environment affects how genes work and genes determine how the environment is interpreted.

Most people are delighted with all the new information about the organ that is most curious to us. But some don’t believe it and others are afraid of it, convinced that such research is a plot to discriminate against some groups, or gain mind control over others.

I suppose it is somewhat disconcerting to realize that our thoughts are created by molecules, and that the molecules are manipulated by our experiences. But, instead of being limiting, or threatening, I believe the new knowledge about the brain is enlightening and liberating.

My foray into this revolution began in 1992, when then editor of The Chicago Tribune, Jack Fuller, was getting ready to launch a yearlong project called “Killing Our Children.” He asked if there was anything going on in brain research that might be helpful. For me that was like being given the keys to the candy store.

As I began to dig in, what initially turned me on was the work of the University of Chicago’s Peter Huttenlocher. He was, for the first time, counting synapses, the telephone lines that enable brain cells to communicate with each other. These connections are so small and so numerous that they had previously defied a scientific census.

From autopsies of the brains of fetuses and people ranging in age from a few months to their nineties, he took samples about the size of the head of a pin, each containing about 70,000 brain cells. In a sample from a 28-week-old fetus he found 124 million connections between the cells. The same size sample in a newborn had 253 million synaptic connections and in an 8 month old the number exploded to 572 million.

At the fastest rate, connections were being built at the incredible speed of 3 billion a second, eventually reaching a total of about 1,000 trillion connections in the whole brain. After that point, the connections begin a gradual decline. By about age 10 or so, half the connections have died off, leaving about 500 trillion, a number that remains fairly constant through most of life.