Change Blindness and Self Protection Training

This article developed out a series of notes on cognitive psychology as it can be applied to self protection (and general fighting skills) training, specifically the different types that we use, and what causes our attentive processes to fail.

Generally speaking, our brains devote more effort towards ignoring stimulus than processing it- roughly 5% of available stimulus is selected to be processed as perception and the rest is selectively ignored. Despite our subjectively rich experience of the visual world, the portion that we can usefully focus on is relatively small and subject to perceptual limitations. The small facets that we do focus on take up valuable neurological “real estate” and each additional detail that we attempt to focus on takes up more of this limited resource. If we focus on multiple things at once, we’re more likely to ignore aspects of each thing that we are focusing on, causing attentive failures (texting while driving, anyone?).

One type of attentive failure is referred to as “change blindness.” If a brief disruption in visual continuity occurs while we are viewing a scene, large changes may occur in that scene without our noticing them when our attention returns to it. The effect is easy to demonstrate using flickering pictures, which cause a global disruption (a brief but total disruption of the picture being seen). Frustrating, no? Some of the changes occurring in such pictures can take as long as one minute to register. Once you notice them they’re shockingly obvious. Here’s one without the flickering to illustrate how the same changes are immediately obvious when our attention is focused without any disruptions. Much easier, right?

Here’s an example of local disruptions (in which small portions of the scene are disrupted, simulating a mudsplash or strobing lights). Again, the partial disruption of the image we are seeing causes the same difficulty in registering a change when our attention returns to the full scene. Apply this to a scenario where there are multiple moving features obscuring part of the visual field, such as flashing lights, debris or fluids (blood, mud, a thrown drink, etc) splashing the eyes, and the aspect that you are focusing on is suddenly out of the picture. Whatever changes occur during the visual disruption may be harder to notice, or go unnoticed as you refocus on the original target.

To put this into a training context, replace the term “disruption” with “blink,” “wince” or “glance,” and the same attentive failures happen. Most of us have had the experience of squaring up with a partner during training, blinking or looking at the clock, and suddenly being nailed by a punch or kick that we never saw coming. Or try randori with this variable: once a pair is engaged in close, intense grappling, throw a “weapon” onto the floor while their attention is diverted from the larger scene and see how long it takes for either one to notice it (this will work best if neither of them expect it). The failure to register a change in your partner’s status or the larger visual scene is the same change blindness that we experience with the flickering pictures. If our visual attention wanders or is diverted for as short as a few milliseconds, the approach of a fist or a change of facial expression from neutral to aggressive might go unnoticed.

The work with static pictures is interesting, but what about live interactions between people? The same change blindness can be demonstrated between two individuals, provided that there is a global disruption of the visual input. (embedding is disabled for this clip, but clicking on the clip will open it in YouTube)

Again, applying this to training contexts has obvious implications. If for example you are actively attending to someone in your field of vision who appears threatening, and your attention is diverted by glancing at another person, someone passing between the two of you, or by turning to look for the source of a noise behind you (each is a global disruption, the same as caused by the obstacle to the volunteers’ visual field in the clip above), change blindness may affect your ability to accurately judge important changes in the initial person’s posture, emotional affect, the presence of a weapon, or their spatial relationship to you. In the case of the volunteers in the clip, 3/4 of them did not realize that they were in fact talking to two different individuals. Other experiments (Simons & Levin, 1998) involve an actor asking a random person in public for directions. As the directions are being given, two volunteers walk between the actor and the subject with a large door, causing a global disruption. While the door is between them, the actor is replaced by a different actor. As in the clip from Harvard, a majority of the subjects failed to realize that the person they were talking had been replaced.

If we extrapolate from these findings to scenarios dealing with multiple threats or attackers, the disruptions to our attention multiply with each threat or attacker that is present, which means that the opportunities for us to fail to register significant changes multiply as well. If added factors are present, such as a strategic need to defend another individual or hold off a violent individual until help arrives, our attention is divided even further by mental distractions. The further our attention is divided, the higher the chances become that we will fail to register crucial changes in the scene at hand.

This phenomenon becomes especially important if we apply it further to scenarios involving multiple attackers. It’s often claimed that “kata/forms are a defense against multiple opponents.” However, how often is this claim substantiated by training methods that realistically create the chaotic attentive disruptions presented by an assault involving multiple attackers? When watching typical demonstrations of such defense scenarios, several major shortcomings are obvious: the “attackers” always wait for the defender to face them, signaling readiness and attention to the incoming attack; the “attackers” always attack one at a time; the “attackers” always wait for the defender to finish responding to the attacker at hand before attacking; the attacks are usually singular, and the “attacker” remains in place and does not resist as the defender responds. By allowing the defender to focus his attention on one threat at a time at a measured pace, the possibility for change blindness to occur is artificially limited. This may be helpful for the purpose of putting on a clean demonstration , but such scenarios do not address the attentive disruptions that are going to be present in an encounter with multiple attackers. Training in this sort of representation offers little practical value to a student, and may actually encourage the attentive behaviors that create the opportunity for change blindness to occur.

On the other side of the coin, it is certainly possible to deal with multiple attackers, despite the inherent attentional disruptions. The video clip below shows a man being assaulted by multiple attackers and successfully dealing with all three of them at once. Just a cursory viewing makes it clear that many distractions are present, yet he sustains little injury and manages to effectively repulse each attacker.


We can draw a few conclusions from this clip about the nature of the environment the defender faces, and the reasons for his success at effectively responding to it. From the outset, the defender is dealing with three attackers approaching or attacking at once- they do not take turns, and they all attack at least two or more times. As he responds to the attacks, the defender moves along the periphery of the crowd and backs away from the attackers that he has downed, which allows him to keep the entire scene in his visual field at once. By keeping the attackers in front of him throughout the engagement, he runs less risk of losing track of one attacker as he turns to face another, and thus reduces his chances of being blind to a change in the status any one of them. An example of this can be seen beginning at :34, where the defender parries a flurry of blows from two attackers simultaneously and immediately moves to engage a third attacker as he approaches. Throughout the engagement, the defender’s head is facing squarely at the oncoming attacker, and instead of turning his head to look at the next one, he moves his body in a way that allows him to keep all threats in the same visual field at once. Since no one is ever totally obscured from his field of vision, attending to all three at once is possible. Despite this, there are still several local disruptions (fists, arms, bodies), and the defender does take a few hits- but overall he does a remarkably good job of limiting the disruptions to his visual/attentive field. This is just one example, and the presence of more attackers or traffic may have produced a different outcome. But such scenarios, coupled with a knowledge of attentive failures, specifically change blindness, raise the following questions:

1. What aspects of a threatening or violent scene (involving environmental distractions or multiple attackers) present global or local disruptions to our visual/attentive field;

2. How do those disruptions affect our ability to respond efficiently to changes in the scene (incoming attacks or changes in an individual’s threatening behavior);

3. What strategies can A) enable us to attend to multiple aspects of such scenes and limit the global and local disruptions to our visual field, or B) to ignore distracting stimulus, thereby reducing the opportunity for change blindness to occur;

4. How do we incorporate those strategies into our training;

5. How do we represent such scenes and distractions realistically during training in order to apply and refine those strategies (#4) in a useful way.

This is just a brief summary of the topic and it’s relationship to self protection training, but it bears further investigation. Until more serious work is done in this particular line of inquiry, we can reflect on it’s implications for our training practices and our everyday experience. Particularly in an era when many of us continually stare at devices in our hands or compulsively divert our attention to invasive media, it’s important to ask ourselves “What’s going on around me, where is my attention focused, and what am I missing?”


One response to “Change Blindness and Self Protection Training

  1. Randy,

    you might be interested in Bruce Siddle’s books On Combat (w/ Dave Grossman) and Sharpening the Warrior’s Edge- these books cover some of what you talked about here.

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