The duration of thinking can vary greatly for a variety of reasons

But the duration of a thought will vary significantly depending on its routes,pitstops, and destination.In this case, when you perceive a threatening stimulus,you'll invoke a fear startle response.Similar to the knee-jerk response,a startle can be involuntary and quite fast.If the string twangs loud enough,you might react in less than 65 milliseconds.More likely though, your startle reaction will be based on sight.Our eyes can process an image as quickly as 13 milliseconds,but computation of what you're seeing and determining the danger it poses can take as long as 180 to 200 milliseconds.In that time the arrow will have gained a head start of about 13 meters.The target is far enough away that you're got just enough of a chance to catch up,if you can quickly, and quite literally,think your way out.