John Stern first became interested in blinking during the Watergate scandal.

As a psychologist concentrating on physiological gestures, he was fascinated by the way politicians blinked.

"President Nixon's blink rate markedly increased when asked a question he was not prepared to answer," the chairman of the psychology department at Washington University said. "His speech was well-controlled and did not manifest other symptoms of anxiety, but you could see it in his eyes. Most politicians have learned to disguise feelings except in ways they cannot inhibit."

Stern has pioneered the field of blink wave form. Instead of measuring the rate of blinks, as other scientists have, he found that blink shape tells more about alertness and frame of mind than blinking speed.

"We do not just blink at random," Sterns said. "We blink at times that are psychologically important. They are the brain's punctuation marks. Their timing is tied to what is going on in your head."

In one study, he awakened pilots in the middle of the night and kept them awake to fly a 4 1/2-hour simulation 12 hours later. Using aspects of blinking and eye movement, researchers found a high correlation between blink measures and errors in flight performance.

In his St. Louis lab, Stern is examining people's ability to concentrate on sounds.

"If somebody blinks while listening to a tone, he is more likely to give a wrong answer to questions," he said. "As his concentration shuts off, he blinks."

Stern has found that when a person has to make a decision during a simple task, he blinks more frequently. When he hears long or short tones and has to distinguish between them, he blinks at some point in the decision-making process. If asked to perform a simple multiplication, a person may blink as each point of the problem is solved and stored in the mind.

Stern has found that traffic affects a driver's blinking. Drivers blink less frequently in city traffic and close their eyes for shorter periods of time. People have more freedom to blink on highways, and they take advantage of it.

He has found that blinks vary according to the importance of an event. To routinely check speed, a driver blinks in one manner, but when a police car is following, the motorist blinks far less frequently.