I have a friend ( Robin Brown )that trained with James Keating for 9 or 10 or more years in knife training and this is what he has to say about this. I first used the term "Startle Response" on the net on 7-12-2004, 12:02 PM in a post on another forum after a defensive edged weapons class I held in NYC the weekend before. I have used the term since at least 1997 in my defensive edged weapons classes. By the time I was given the role of adjunct defensive edged weapons instructor at S+W's training facility in Springfield, Massachusetts in 1999 I was using the term regularly to describe ones initial reaction to perceived danger. What is the "startle response"? In a nutshell, it's the O' sh*t mental feeling one gets and it occurs when they are behind on the reactionary curve and taken by surprise by something that might be as simple as a car backfiring, or a baloon popping, or in the worst cases, possibly being physically attacked without warning/notice either from behind or a frontal assault, or maybe attacked by someone who has just produced a knife or gun from nowhere with no apparent prior intent to harm you, no "preassault bahavioural pattern" detected. By the time one can say O' sh*t and your brain has the time to comprehend thinking it, it could be too late to prevent physical contact with an aggressor/assailant. It may only take a split second for the brain to think it consciously, but in the time it takes the brain to realize there is potential danger and get the muscles moving in some form of reaction, potentially fatal damage can be taken. How do people normally react to being startled under perceived imminent danger of taking some type of physical damage? In the same way people who see imminent danger coming like a knife attack, by raising their elbows up and away from the body, extending the one or both forearms out to meet the threat along with the hands with palms facing outward. Why do people react this way? It most likely is a natural response our ancestors developed in an attempt to keep the danger initially at some greater distance to us if possible. Animals do the same thing if they have limbs. They reach out with their claws extended like cats will do when threatened, in an attempt to keep the danger from getting any closer. Is our natural response at using our arms and hands something we should be doing to protect ourselves when startled? Does our natural startle response to danger help us or leave us open to fatal damage to the body? It can go both ways at times, so there is no right answer and it becomes situationally dependant on the circumstances as well as what the immediate danger is [ which we may not be able to recognize before our startle response kicks in subconsciously. Ever seen photos of a victim who was attacked with a knife? Lots of what are known as "defensive wounds" to the forearms and hands. We use our limbs to protect us from danger, in attempting to keep the danger away from us naturally. It's the natural response damage seen in victims of this nature. Most will move their arms and elbows away from their body to keep that danger farther away in an attempt to protect the head and body from any damage using their natural startle response. In unarmed defensive edged weapons training, if we use our natural startle responses to danger, we are giving the aggressor targets of opportunity that are closer to hit [ the outstretched arms and hands ]. At the same time we are opening up the body's core and risk getting nailed where the real immediate life threatening damage occurs. It's obvious in class that if we extend, we take damage to the core more often than not. If that extension occurs due to our using the body's natural startle responses, and thats a bad thing, the next question would be, what can we do to train that natural reponse of extending out of the startle response. Good unarmed defensive edged weapons startle [ or otherwise ] responses will make use of the arms and hands to "protect the core" at all times. That requires the mind to ignore the natural response to extend, and instead endeavor to protect the core by collapsing onto itself and keeping the limbs close to the body. One can train their startle response to use this collapsing upon itself with the forearms and hands staying as close to the body's core as possible [ from the belt to the head ] while under imminent danger and a response to being startled. In doing so one has accomplished a few things, all beneficial to surviving the first second of an attack. First we protect the body's core immediately with the arms and hands as shields that have to be breached; second we do not give aggressor targets of opportunity [ the hands and arms ], and the third real benefit is that by collapsing/retracting the arms and hands into to the body we have made the attacker have to extend his own arms/hands further which then takes more time to get to us, but at the same time makes the power of the attack when it does connect less effective. How does it make the power of the attack less effective? I'll use an example I use in classes which is readily apparent to everyone. When you pick up a 5 gallon bucket of paint, do you pick it up with an outstretched arm or do you pick it up and keep the bucket and arm retracted and close to your body? The answer is the latter, and it's obvious now why and it is because the arm loses power the further it gets from the body. So, the power of the attack is less when it reaches us if the aggressor has had to extend his arm further and conversely we retain our power in the arms by keeping them closer to the body at the same time. More power to defend and less power from the attack when and if contact is made. Makes sense right? It goes against our natural startle responses but it keeps our core better protected from taking damage. Learn the "collapsing startle response" © TM. The article wasn't written with the intent to explain how the collapsing startle responses are used, the techniques if you will. It was to get people to understand that if they only use their natural startle responses they give the aggressor advantages that are unnecessary. It doesn't have to be used just against a knife and you'll likely not have time to determine what the aggressors intentions are or what he holds in his hand. It may be just a punch coming in, or something else held in the aggressors hand. If you don't survive the initial second of the attack, if you didn't protect the core in that startle response of yours and took real damage, then even if your subsequent actions get the aggressor to cease and desist afterwards, you have not won at all.