Editor’s Note: Because I don’t have access to any of the information being examined by the grand jury in the shooting of 18-year-old Michael Brown in Ferguson (Mo.), I aim here to begin addressing some of the physics, physiology, and psychology of this type of incident — not the incident itself. I don’t know how many shots in total were fired. I don’t know how long this event took. I don’t know if the alleged audio recording of the incident is accurate because the FBI has not yet released its analysis of the veracity of that recording. In this space and other articles to follow, I will make reference to Ferguson whenever relevant or pertinent to the current public discourse on it, but will principally be examining the science of human performance and the dynamics of deadly-force encounters in general.
It’s time to talk about time. There are a lot of pundits — who know precious little about police work in general, let alone the Ferguson OIS in particular — crowing about the number of shots fired that August afternoon in Ferguson. “How is it that the officer had to fire so many shots?” and “How can it be that the officer still felt fear for his life at the sixth shot?”
Left out of all of the so-called analysis of Ferguson in the mainstream media is any real examination of the science of human performance during rapidly-unfolding, high-stress events. For answers regarding the science of a use-of-force event, we need to look no further than the research from Force Science Institute, so I recently spoke with Dr. Bill Lewinski, FSI’s Executive Director.
The first topic in that discussion was the question of time. On the part of the officer, we spoke about time to start a response, time to perform a response, and time to stop a response. We spoke about the time it takes for a person to move their arms, to cover a distance of seven feet, as well as the time it takes a person who has been fatally shot to fall to the ground.
Time to Move
In a study conducted by Force Science Institute in 2013, it was discovered that the average individual can cover the distance of seven feet — without reaching forward — in two-thirds of a second.
If a person is even walking from such a distance toward an officer, we’re talking fractions of a second before that gap is closed.
The findings of that FSI study help us better understand an officer’s vulnerability to an offender at relatively close distances armed with an edged weapon, a blunt instrument, or hands, feet, and fists — as was the case in Ferguson.
It is important to note here that Michael Brown was six-feet, four-inches tall, and weighed just shy of 300 pounds. He had been in a violent struggle just ten minutes before his deadly confrontation with Officer Darren Wilson (and reportedly assaulted the officer), indicating the level of threat the officer may have perceived Brown to be at the time of the shooting.
“Another issue is the mobility of a human limb,” Lewinski said. “An arm can move from over the head to down by a person’s side in 14/100 of a second. A body can move from an erect position to bent-over at a 45-degree angle in a half a second or less. That’s easy to do, and it’s easy to demonstrate, and we’ve got it in our research.”
Incidentally, that one data point on the arm is one reason (among many) why any argument about having officers “shoot to wound” is specious — an arm can move so fast it is almost impossible to intentionally hit it. So let’s please put that ridiculous line of “reasoning” to rest.
A person beginning to charge another might make that motion from an upright position to a bent-over position, and given FSI’s research, that can happen very, very quickly.
Finally, let’s consider the time it takes for a person who has been fatally shot to fall to the ground, which has relevance for both the subject as well as the officer in such events — and may have been a factor in Ferguson.
“We’ve got 20 examples of people who were shot and immediately died and before we see any movement at all on the part of the body, the person doesn’t move for a quarter of a second. Then, it can take up to nine-tenths of a second for the subject to go prone on the ground,”
Lewinski emphasized that the way in which a person falls is critical. If a person is falling forward, where the head is parallel to the ground — essentially face toward the ground and pointed toward the officer — that motion can be accomplished in a half a second or less. We’ll revisit this time factor again in the next section.
Time to Shoot
With the science behind some of the movement covered, the factors of officer shootings need to be considered. Those factors include time to start, duration of the shooting — remembering that six rounds can go out in one and a quarter seconds — and time to stop.
“Looking at time to start, we’re looking at an absolute minimum of a quarter to a third of a second for an officer to recognize the threat and begin to react. If we’re looking at someone stepping forward toward the officer — or even stepping back — that means they’ve stepped either forward or back in the timeframe it takes the officer to even make the decision to shoot, let alone the time to implement that decision. So we can have dynamic motion on the part of the subject occurring within a very brief period of time.”
We must remember also that perhaps the most baseline level of this discussion is the cadence of fire for the average police officer. According to research by Force Science, the average officer takes .25 seconds to fire a round — meaning that a cadence of four rounds per second is quite common. Whether it was six shots and six hits or ten shots with six hits in Ferguson, we are talking about a very, very brief period of time.
We must also remember that it takes time to stop shooting. It takes time to even perceive and process a change in the threat level presented by the subject. And during that time, an officer — who is engaged in continuous rapid fire, as their training requires for defending their lives — is still delivering rounds to the target.
In a very recent report about a new research paper on this topic by Lewinski and the FSI team, it was stated that “if an officer were to take [merely] 0.56 seconds to react to a stop-shooting signal, approximately three [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.”
“It also takes time to detect change, and depending on what an officer is focused on, they may or may not immediately detect change on the part of the subject,” Lewinski told me during our conversation this week.
If reports are confirmed that Officer Wilson had been beaten pretty severely about the face — and some damage was done to one eye — that will have an impact on his ability to detect a change in the threat level posed by Brown. If you have significant facial damage, in conjunction with the fact that you’re involved in a physically demanding fight, those factors can increase the time it takes to sense any change in the subject’s threat level.
“Certainly someone could move, and fall to the ground, and your ability to detect change and make a decision to stop could take longer than the time it takes for that subject to go from an upright position, to a horizontal, almost prone position.” Lewinski explained.
Going back to Ferguson, this could explain how the fatal shot entered the top of Brown’s head, as it appeared from the publicly-released autopsy commissioned by the family.
“When you look at shooting times — with a duration of somewhere in the realm of a second to a second and a half — with multiple shots and dynamic movement of a body, including moving forward, you’re going to have some unusual angles of shot placement, including into the head,” Lewinski said.
“We’re not saying that happened in Ferguson, but the factors of human movement and time need to be considered,” Lewinski concluded.
