Most of us blink about fifteen times a minute. We do sometimes to protect the eye. Much of the eye is guarded inside its socket. a bony cavity padded with fat, and that, in turn is shielded by the skull. But when your eyes, the body’s most delicate sensors, are wide open, about one-tenth of their total surface is fully exposed to the atmosphere, to winds and possibly to dust.
The eyes need constant lubrication. Also, their front portion, which gathers light, must be kept crystal clear for good vision. Blinking serves this double purpose. The eyelids snap shut and flip open again, coating each eye with a film of tears, rinsing away fine debris, to clean and lubricate the surface. Frequently, we blink for other reasons, such as to guard our eyes against a sudden blow. Loud noises may make us blink and so may anxiety. Using hidden camera, infrared lights and other specialized equipment, scientists have studied the eye reactions stances, such as at meetings, driving in traffic and under various kinds of stress.
Their findings show that we blink less when we are alert. Someone reading a novel blinks about six times a minute, but people in conversation blink twice as often. Car drivers blink less in city streets, when they need to concentrate more closely, than when out on the open road.
When we are bored, we blink for longer. In one experiment, people were asked to listen to a protracted and deliberately boring series of tones. As the rest went on, the duration of each blink increased by more than 30 percent. Nervousness makes us blink more frequently. That is why TV newsreaders are coached to blink normally. This gives them an appearance of calm control. Lawyers say that witnesses under cross-examination blink more frequently than those facing more friendly questioning. And if politicians blink too often in a television interview, it’s usually interpreted as a sure sing of tension. When George Bush and Michael Dukakis engaged in a TV debate in October 1988, Dukakis averaged seventy-five blinks a minute to Bush’s sixty-seven.