When in stressful situations, people develop tunnel vision where they tend to see only what is directly in front of them; this is called tunnel vision. In combat, this is dangerous. You must learn to defocus the eyes, not stare at one object, and be aware of all surroundings. To deceive the opponent, it is better not to look directly at the target, but to use your peripheral vision. Squinting helps reduce the field of vision to that of just the opponent. Also, movement is detected more quickly with peripheral vision than with direct vision, so it is best not to watch the opponent directly. Another technique is to look directly into the opponent's eyes but to look beyond the eyes so it seems as if you are ignoring the opponent. Miyamoto Musashi, Japan's most famous swordsman, stated the following in his Book of the Five Circles (Gorin-no-sho).
"From ancient times we have been taught many ways to direct the eyes, but the one used at present is to look at the opponent's face, to narrow the eyes more than usual, and to maintain a calm gaze. The eyeballs must not move and should see a nearby opponent as if he were slightly in the distance. Such a gaze permits one to observe the opponent's techniques, of course, and also allows one to see what is happening on both sides of one's body. The soldier must always see distant things as if they were close at hand and nearby things as if they were distant. He must know about his opponent's sword without actually looking at it."
A calm, cool, penetrating stare that seems to plumb the depths of the soul awakens feelings of insecurity and discomfort in the opponent and disturbs his or her concentration. This technique also works for the opponent, so if you feel you cannot beat your opponent in a staring contest, it is best not to try.
A 1999 study by Williams and Elliott, Anxiety, expertise, and visual search strategy in karate, found that when visually scanning an opponent for movement, the most efficient pattern is one with fewer fixations of longer durations. Expert fighters fixed their gaze on opponent’s head and central body, while using peripheral scanning the hands and feet. The anxiety of competition tends to cause an increase in search rate and an increase in the amount of time spent fixating on the periphery. It causes a decrease in viewing time overall and an increase in response accuracy. Under anxiety conditions, novices reduced fixation duration whereas experts increased the length of fixation duration. Novices also increased the number of fixations and the number of fixation locations
A 1999 study by Williams and Grant, Training perceptual skill in sport, found that elite athletes do not have superior visual ability and that training vision does not improve sports performance. However, skilled athletes do:
- Have better perceptual skills and are more capable of selectively attending to, recognizing, analyzing, and interpreting incoming visual information.
- May recognize and recall playing patterns more quickly and accurately.
- Are better at anticipating their opponent’s behaviors through efficient visual search strategies.
- Are more accurate in their expectations of their opponent’s reactions.
The study also found that that perceptual abilities may be trained by using simulation, such as watching videos from the competitor’s perspective, stopping the video prior to critical interactions, and having the viewer predict the reaction or have the viewer react physically based on the prediction.