Clearly, the way we use our eyes - that is, conscious control of eye movement and direction - is important in Shintaido and other martial arts. A recent article by Devon Powell about magicology (the scientific study of magic and illusion) in New Scientist magazine (24 December 2008) sheds some light on both the practical martial arts applications and the philosophical implications of consciously controlling our eye movements.
An excerpt from the article:
Over the past decade or so it has become clear just how scarce attention is: focusing on one thing can make you oblivious to other things that would otherwise be obvious....
[Researcher Gustav] Kuhn recently demonstrated this using a trick where he makes a cigarette and lighter "disappear". In truth he simply drops them into his lap when your narrow spotlight of attention is pointing elsewhere.
By tracking eye movements as people watched a video of the trick, Kuhn showed that people miss the deception even when they're looking directly at it. It works because, at the crucial moments, he makes attention-grabbing gestures and eye movements that divert attention (but not gaze) away from the action....
During his training as a professional thief [pickpocket], [Apollo] Robbins was taught to use two types of hand motion to control his victims' attention. Slow, circular hand motions are good at engaging and keeping attention, while fast, straight ones are useful for quickly diverting it from one spot to another.
There are several eye-movement training methods in martial arts that I'm aware of. In some styles of T'ai Chi an unfocused attention covers the whole visual field, enhancing peripheral vision. In other styles the eyes are focused on the hands as they move. In karate partner sparring, I was taught to focus on the opponent's chest or on an area above the head, but to avoid looking at the eyes. (This may relate to avoiding focusing on social cues such as the other person's eye movements and facial expressions - see below). Certainly there are many other eye-movement training methods in other martial arts, meditation techniques, etc. that I'm not familiar with.
In Shintaido we often use distant eye focus, focusing beyond what we "actually" see to the infinite distance. This suggests that we are training ourselves to focus beyond that which grabs our immediate attention - which, in the context of self-defense, could potentially mean another person's attempt to misdirect our attention in much the same way that magicians or pickpockets do. (There are some other eye-movement training methods in Shintaido, such as the meditation described by Aoki-sensei on page 209 of his textbook Total Stick Fighting: Shintaido Bojutsu).
At the same time, this practice of literally looking beyond the illusion could function as a practical method for exposing the mechanisms of perception to conscious observation or control. A further excerpt from the New Scientist article:
A second key tool in the magic repertoire is illusions, particularly cognitive illusions. These rely on the fact that much of what you think you see is actually invented by your brain. Perception is not about capturing a full picture of reality, but taking snapshots of the world and making the rest up.
In the vanishing ball illusion, for example, a magician tosses a small ball up and down while following it with his eyes. He fakes a third toss, keeping the ball in his hand but still moving his eyes as if watching it. This reliably creates the illusion of the ball being thrown upwards - then disappearing into thin air.
Kuhn recently brought this trick into his lab to examine how it works. By tracking people's eyes as they watched it being done, he found something unexpected. On real throws, the eye movement of subjects followed the ball's trajectory. But on the trick toss, their eyes remain firmly glued on the eyes of the magician. This, says Kuhn, shows that the brain overrules the eyes and creates an image of an object that doesn't actually exist....
The trick also relies on another glitch in the visual system. Information captured by the retina takes about 100 milliseconds to reach the brain. To compensate for this lag, the brain predicts what the world will look like in the near future and acts on this prediction rather than the real information at its disposal. This is useful in real-world situations such as driving a car, but it also gives magicians an opening to exploit.
(A fuller report of the research by Kuhn and Land is in Current Biology).
While this phenomenon is about seeing something which isn't there, you can experience another well-studied perceptual phenomenon by watching a video on-line. Before you read any further, try to precisely count the total number of bounces of all the basketballs in this video.
If you didn't see the person in the gorilla suit walk through the middle of the scene (about 50% of test subjects don't), you have experienced "inattentional blindness," which occurs when we are strongly focused on certain things and literally do not see something else that is right in front of our eyes. This was demonstrated in the well-known experiment conducted in 1999 by psychologists Daniel Simons and Christopher Chabris (of which the video was a part). (An abstract is here).
What all this implies is that perhaps by consciously controlling our eye movements we can influence the reality-generating function of the brain's visual perception system (as mentioned, the real information from the eyes is there, being fed into the brain but being ignored). This would significantly change the way we are programmed to perceive reality. Concretely, what we do in Shintaido practice is to enter into a social situation - kumite or partner exercise - while simultaneously keeping a visual focus beyond the other person, beyond walls of the room or the limitations of the physical environment, and beyond the social cues that influence us to see as we are programmed to.
In a more philosophical context, it seems the very same techniques embodied in martial arts and Shintaido practice speak to seeing beyond the Maya, the veil of illusion that we mistake for reality. By looking beyond, we avoid getting caught up in the illusion of what we think we see or what we are subtly being told to see. Paradoxically, this may help us to see more clearly what is right before our eyes.