Thank you for joining us for Spotlight. I'm David Bast.
How good is your memory? Can you depend on your memories to be correct? Today's Spotlight is about memory.
Paul Doherty is a writer from the United States. He describes a memory for us.
"I, my friend Martin, and a small group were climbing in the mountains. We climbed with two ropes. Martin and I climbed using the first rope. We had already reached the highest point of the mountain. And we could see that a storm was coming. We knew that we needed to protect ourselves. We climbed a little way back to a shelter area. We would be safe there.
Not all of the people in our group had reached the top of the mountain yet. They were using the second rope to climb. So we stayed at the shelter to wait for them.
I can still see it like it was yesterday! People on the second rope were still climbing the side of the mountain. The lightening came from the sky. It hit the rope. Some of the people in the group were still using that rope to climb! The people on the rope were not seriously harmed. But they were very frightened.
Paul keeps a journal, a book where he writes his thoughts. He also writes about the things that happen to him during the day. A few years after this climbing incident, Paul looked back at his journal. He looked at what he had written in his journal about this incident. Paul was shocked. His written story and his memory were different!
What really happened then? Well, Paul and Martin did climb from the mountain top back down to the shelter. But, they decided to take turns waiting on the edge for the second rope of climbers. One stayed by the edge of the mountain waiting. And the other stayed in the shelter to keep warm. Then they traded positions. Paul was not at the edge of the mountain to help the climbers up. In fact, his friend Martin was the one who had helped the second rope of climbers up! Paul was back at the shelter!
Paul remembered something that never really happened! His journal had the real story. But his memory was wrong. However, he says he remembers the event clearly! So, can we really trust our memories? What can we believe?
Some people believe that memories are stored like pictures in a person's mind. If a person wants to remember a particular event or story he goes to a special part of his brain. Then he just pulls the memory out. If this is the case, a person's memory should be perfect. All he has to do is look at the 'picture' in his mind to remember it.
But researchers say this is not how it works. Instead, our memories are much more complex! Experts say that our brains divide our memories into many parts. The brain stores the sounds, sights, smells and tastes that you remember in different areas. Let's look a little closer at how the brain recreates memories.
The brain has an outer layer around an inner mass. The outer layer is called the "cortex". The cortex is only a few millimetres thick. But it holds about seventy thousand million [70,000,000,000] brain cells!