Any of you who have ever tried speaking in front of people will appreciate the predicament that Dr. Ralph D. Nichols of the University of Minnesota once found himself in. He was addressing a high school commencement when suddenly a child began to cry. That was distracting, but not too much of a problem. But then another child added his loud voice. And then a couple of small boys started galloping up and down the aisle. With the sinking feeling only a public speaker knows, Nichols realized he had lost his audience.

Nichols tried every trick of the speaker's trade: he spoke more loudly, he told a funny story, he walked around the stage, and he peered intently and disapprovingly at the area of disturbance. But it was all to no avail.

Then he tried his last desperate trick. He found one good…