I'll tell you the incident in New Guinea that had the biggest influence on my subsequent life. I was with a group of New Guineans doing a survey of birds on a mountain, and we were establishing camps at different elevations on the mountain to survey birds of different elevational ranges. We were moving from one camp up to another camp, and so I'd wanted to choose a new campsite. I found a gorgeous campsite. It was on a place where the ridge broadened out and flattened out. It was a steep drop-off, so I could stand at that edge and look out and see hawks and parrots flying. The broad area of the ridge meant that there was going to be good bird-watching walking around there. And it was beautiful, because my proposed campsite was underneath a gigantic tree, just a gorgeous tree. I was really happy with this campsite. I told the New Guineans, “Let's make camp here.” And greatly to my surprise, they were frightened out of their minds, and they said, “We're not going to sleep here. We'll sleep out in the open, rather than sleep in tents here.” I said, “What's the matter?” They said, “Look at that tree. It's dead.” Okay, so I looked up, and yes, this gigantic tree was dead, but it was solid as iron. And I told them, “All right. So maybe it's dead, but it's going to stand there for another 70 years, it's so huge and solid.” But no, they were just terrified, and they were not going to sleep under that dead tree. They actually did, rather than sleep under the dead tree, they went and slept 100 yards away.
We stayed at that campsite for a week and naturally, nothing happened. I thought that the New Guineans were just being paranoid. And then, this was early in my career, as I got more experienced in New Guinea, I realized, every night I sleep out in New Guinea forest. At some time during the night, I hear the sound of a tree crashing down. And, you see tree falls in New Guinea forest, and I started to do the numbers. Suppose the chances of a dead tree crashing down on you the particular night that you sleep under it is only one in 1,000. But suppose you're a New Guinean, who's going to sleep every night in the forest, or spend 100 nights a year sleeping out in the forest. In the course of 10 years, you will have spent a thousand nights in the forest, and if you camp under dead trees, and each dead tree has a one in 1,000 chance of falling on you and killing you, you're not going to die the first night, but in the course of 10 years, the odds are that you are going to die from sleeping under dead trees. If you're going to do something repeatedly that each time has a very low chance of bringing disaster. But if you're going to do it repeatedly, it will eventually catch up with you. That incident affected me more than anything else, because I realized that in life, we encounter risks that each time the risk is very slight. But if you're going to do it repeatedly, it will catch up with you. And ever since then, I'm now very cautious about how I stand in the shower, how I walk on sidewalks, how I go up and down stairs, how I take left turns in my car.