Page 48 - The Memory Program How to Prevent Memory Loss and Enhance Memory Power

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cause, memory loss as you grow older. These effects can be directly altered, unlike your genes. I will
focus on these environmental, usually reversible, factors in a later section in this book.

Aging Weakens Recent Memory

Do you remember what you ate for lunch today? How about yesterday? And how about a week ago?
For most of you, whatever happened today is still in active memory, yesterday is hovering above the
“memory trash,” and the meal from a week ago is already in the trash and likely gone for good. The
time factor is crucial; as you go further back in time, memories begin to vanish. The paradox is that
as you grow older, it is not the old memories that disappear but more often the recent ones. Most
recent memories— even if they are closer to consciousness and hence more “active”— are not
hardwired in your brain as firmly as old memories, so you can understand why lapses in recent
memory occur during the aging process.

The Power of Learning

When infant mice are made to learn a complex task like traversing a maze to reach a source of food,
the process leads to increased branching and connectivity among nerve cells in the brain. Learning
literally leads to a structural change in nerve cells in the mouse brain, and these changes can become
permanent, resulting in superior memory and intelligence. In children, we call this education. In the
mice experiments, the branching of dendrites slows down and then stops as age advances, so that
new learning becomes more limited. Similarly, in people, the ability to learn new information is
greatest during childhood and decreases in later life when nerve cells lose their capacity to grow and
branch out to form new contacts with other nerve cells. This topic reminds me of an incident that
taught me a great deal about our capacity to learn, and how this changes as we grow older.

Back when I was at Yale, I met Anil Deolalikar, an economist who was then a junior faculty
member. Later, he got married and settled down in Seattle. When I visited him there, his daughter
was barely three years old. One morning, he played a game in which he showed her several large
cards filled with red polka dots closely packed across the white surface. One card had sixty-seven
dots, another sixty-nine,