BILL MORGAN, an emeritus professor of kinesiology at the University of Wisconsin, likes to tell the story, which he swears is true, of an Ivy League pole vaulter who held the Division 1 record in the Eastern region.

His coaches and teammates, though, noticed that he could jump even higher. Every time he cleared the pole, he had about a foot to spare. But if they moved the bar up even an inch, the vaulter would hit it every time. One day, when the vaulter was not looking, his teammates raised the bar a good six inches. The man vaulted over it, again with a foot to spare.

When his teammates confessed, the pole vaulter could not believe it. But, Dr. Morgan added, “once he saw what he had done, he walked away from the jumping pit and never came back.”