The difficulty with predicting behavior

When I first started teaching at CWRU over twenty years ago, I recall giving a physics final exam in which students wrote their answers in the familiar blue books. When I started grading them later, I found one in which the student had made little or no attempt at answering the problems. Instead he had spent the entire time sketching quite elaborate drawings of guns firing and other violent images for page after page. At that time, there wasn’t the heightened sensitivity to violence on college campuses that there is now and no training to be alert to such warning signs, and so apart from giving the student a zero on the exam, I did not do anything.

I personally did not feel threatened and dismissed the whole thing as the work of someone who was merely playing the fool and had spent time watching too many violent films and reading violent books rather than studying his physics. Nowadays, I would immediately refer such a student to the counseling center for possible help. As far as I know, that student never did anything else to warrant concern, at least as far as his time in the university was concerned.

A few years later, I had another student. He was socially awkward and struck me as one of those very smart students who had done very well in school with little effort or work, coasting along on his wits. He was arrogant and had the kind of know-it-all attitude that one comes across from time to time in physics classes.

But in college, there are some things that seem dreary and time consuming but must be done even by the brightest students and one of those things is the introductory physics lab and writing the lab reports. Although I taught only the lecture part of the course and the labs were run and graded by another faculty member, the lab grades were reported to me and I had to include them in my final grade for the student and it was a department rule that if you failed the lab, you failed the course. This student had been doing well in the theory part of the course but had been skipping the labs and was getting a zero. Despite my repeated warnings to him to do the labs or fail the course, he kept skipping them.

Then in the last week of classes, he committed suicide.

His death still haunts me. It is very hard to know why anyone commits suicide. But I still wonder if the thought of failing his physics course, maybe the first course he had ever failed and thus a grievous blow to the image he projected to everyone around him, was the trigger, and makes me wonder if I should have noted any warning signs that he might do something drastic like that and whether I should, or could, have done anything differently. A physics grade is nothing when compared to a life.

These two stories from my own life show how difficult it is to predict people’s behavior by their personality traits. After the fact, we see signs and think we should have known and acted differently to prevent the tragedy but before the fact the signs seem quite ubiquitous and much less ominous, trivial even.

In the wake of last week’s mass shooting, NPR had a good interview on Friday with Jack Lewin, a professor of sociology and criminology at Northeastern University. Lewin pointed out that such killers have many common characteristics.

[M]ost mass killers have suffered some kind of chronic depression and frustration. Over a long period of time, they externalize responsibility, blaming everybody but themselves for their failings. They have some kind of an acute strain, a catastrophic loss – the loss of a job, the loss of a relationship at home, maybe even a terminal illness.

And they have the means whereby they can do a lot of damage. They have training and access to firearms, for examples, which means that the body count may be very large.

Very few mass killers, including school shooters, actually snap. They don’t go berserk. They don’t run amok. They don’t go bonkers. We have so many ways of saying that. But the truth is that most of them are methodical. They plan this sometimes for months. They’ll get the weapons and the ammunition. At Columbine, for example, the planning took 13 months. And that’s not unusual.

But in the audio of the interview (which is missing from the transcript for some reason), he says that though we know the profile of such killers pretty well, this is not helpful for prediction and prevention since there are so many false positives, vast numbers of people who show all the symptoms but do not act out on them. Like me with my students, the problem is that after the fact, we all recall the warning signs but it we started reporting everyone who exhibited any of those symptoms, the counseling centers would be swamped. Most people turn out to be quite harmless.

Lewin also points out that despite the perception that these kinds of mass killings are on the rise, the number of such events per year has been fairly steady for decades at about 20 per year with a victim count of about 150, but that these numbers pale compared to the number of single-victim homicides that are around 15,000 and that this is the real problem. I am sure that I have heard this latter number many times before, but every time I hear it, I am staggered at its size.

Mass killings may serve the purpose of focusing our attention on what we should do about this epidemic of homicides.


  1. Henry Gale says

    In my studies of psychology I learned that the best predictor of future behavior is past behavior.

    I’m starting to think about the relationship between the mother and son in the recent Connecticut shooting. If the shooter was someone who played violent video games and if that was the source of some stress in the mother and son’s relationship perhaps that stress was a trigger.

  2. says

    Let’s not just blame the crazies. The problem is more complicated than that. There are a variety of factors that push people toward violence -- media, social roles, availability of weapons, mind-altering drugs, mental health issues, etc. Each of those factors has an effect to a greater or lesser degree on an individual and if we, as a society, attack a single one of those factors our simplistic knee-jerk response is not going to be effective.

    What we need to be doing is asking ourselves (and perhaps some of the other cultures in the world that don’t have this kind of problem) why Americans are such dangerous, violent, assholes. And work backwards from there. If we take it as a given that everyone suffers stress at various times in their life, then the question is why some of them snap in that particular direction and manner. And then what can we do to detect, reduce, and support people who are dealing with problems like that.

    I had a friend who once thought he was going to snap, and brought all his guns up to store them in my gun-safe. 10 years later, they’re still there. He realized that social pressures, marital problems, and alcohol might combine to make him an unsafe gun-owner. That was an eminently rational decision that he made and there was no need to go further in any direction beyond that: just like “friends don’t let friends drive drunk” only with firearms in the mix. But there’s also the ideas -- where does suicidal or violent ideation come from? Well, we’re constantly blitzed by a popular culture that violentizes our responses to even trivial things.

    This is some complex stuff, and when you see someone offering simple clear solutions to a complex problem you can be sure that they’re wrong or they’re selling that solution.

  3. Marwan says

    A few years ago this happened to me: a pupil stood at my door in the afternoon, he wanted to ask me something.
    Next morning I heard he had hung himself.
    No way I have noted any warning sign. I have come to terms with it, but it remains an awful memory.
    You are not the only one who has failed, MS.

  4. Crudely Wrott says

    I think that we face another generational problem. That is, one that will take generations to solve, if a solution is even possible.

    I leave it up to the reader to find the lyrics to Crosby Stills and Nash. The song is “Teach Your Children.” Of course, that presupposes parents who actually can.

    Oh, that’s stingy of me. Follow this link:

    We will not get rid of guns. They outnumber us. We will not stop people from picking up clubs or rocks or knives.
    What we can do, I hope, is to find ways to know or intuit when someone is teetering on the verge. I don’t know how such sensitivity can be made widespread and effective. What I do think is that if we start making a big deal out of talking about such things with our children, making an issue of noticing personalities and moods and the changes they go through the message may get through. At least some of them will in turn teach their children. And they, in their turn . . .

    This is my ancient hope for a solution to an ancient problem. The hard part is facing up to it, each and every one of us. The sickness is deep within us all. It must be faced. It won’t happen quickly.

    Teach your children. Then trust them. It’s likely the best hope we have.

  5. baal says

    ? what
    Your comment doesn’t make sense to me. If it takes ‘generations’ then the solution isn’t enough. Mood is great and all but you’re overlooking what would make bigger changes on shorter time scales.

    The problem is the US gun & violence culture. The best fix is to change our gun laws to match more restrictive countries and to defund the NRA. We could also start funding mental illness treatment and stop using the court system ‘to get people in the system.’

    We don’t need to harness our intuitions or become more sensitive. We need to identify the structures in our society (i’ve identified 2 here, i’m sure there are more that are relevant) that enable mass killings and allow folks with needs to fall through the (large) cracks. Once we id them, we need to then change those structures.

    If we had decent politics, the policy makers would be the ones doing the id and structural changes.

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