Experiments conducted by Force Science Institute involving 102 experienced law enforcement officers showed that when responding to a simple stimulus in laboratory conditions, some officers were able to stop shooting immediately, but the slowest to stop completed six more trigger pulls. In a
report summarizing the research, Force Science Institute noted, “If an officer were to take [merely] 0.56 seconds to react to a stop-shooting signal, three to four [extra] rounds could be fired by the officer as an automatic sequence after the signal to stop had already occurred … The slower an officer’s reaction time, the greater number of shots [can] be fired before a conscious stopping can occur.”
Some officers were able to react seemingly instantaneously, resulting in no additional rounds while others took up to 1.5 seconds to cease pulling the trigger, resulting in additional rounds being fired. Why is that? As noted above, a multitude of factors come into play, including the other stimuli coming at the officer and the officer’s physical and mental state. Training plays a role too; just as we can get faster at drawing our weapon, we can get faster at responding to a stop stimulus—at least under controlled conditions.
In sum, the speed in which an involved officer recognizes a “stop stimulus” is directly related to how quickly they can sort through the sea of stimuli during a lethal encounter and pay attention to the stop stimulus. Then, and only then, can an officer process the stop stimulus, decide to cease an action, and initiate a motor response (physical movement) to stop an action.
Now let’s consider gunshots to the back in the context of this discussion. It is entirely possible an officer perceives the subject as a threat when the subject is facing the officer—and that by the time the reactionary trigger pull occurs, the subject is facing away. It is also entirely possible an officer can not stop an already-initiated action sequence quickly enough upon perceiving an action indicative of threat cessation (e.g., the subject turning away).