Probabilities and the Boston attack and aftermath

[Dave_LF]

[Note: I split this off from the Parlour, but kept it in Bag End, at least for now - VtF]

1. People are inherently bad at estimating probabilities.

This is a little lasto-ish, but I don't want to start a whole thread.

Last week a big chunk of a major US city was shut down for almost an entire day because a person who killed 4 and maimed a hundred something more was on the loose, and the risk to the public was deemed too high for business as usual.

Here is a statistic casually cited today by an article in my local newspaper:

"The National Highway Traffic Safety Administration said 32,367 people were killed in motor vehicle crashes in the United States in 2011."

This is pitched as good news, because having 32,367 innocent people killed at random in one year represents a historic low (when miles traveled is taken into account).

Why haven't we locked down every highway in the nation?

[River]

Why haven't we locked down every highway in the nation?

For the same reason we collectively flip over a bombing or mass shooting but turn a blind eye towards the thousands of murders, suicides, and accidental shootings that happen each year. When things are too common, we just don't notice.

Also, I assumed that the real reason for the Boston lock-down was tactical and the safety thing was just a smokescreen to get people to cooperate. I'm not sure it worked, given that the guy was found after the lockdown was lifted and that dude in Watertown went out to check his boat and found the fugitive hiding inside. Maybe if the dude had been allowed out of his house sooner he would have found him faster. Or maybe, if there'd been no lockdown, the bomber wouldn't have ended up holed up in a boat like that. Hard to say.

[anthriel]

Intent, perhaps?

Driving is seldom a focused attempt to kill. Bombings and the shooting of cops is a pretty focused attempt to kill.

[halplm]

Far too lasto-ish... especially starting with a comment by me.

[Dave_LF]

I'm not looking to discuss the rights or wrongs of the Boston police action; just reflecting on how bad people are at assessing probability and risk. What anth said is certainly the reason people are more afraid or one than the other, but why should this be? The fact is, if you aren't elderly and you're in good health and don't have any special risk factors, a car accident is by far the thing most likely to kill you in the near future*. It is certainly about a zillion times more likely than a terrorist attack, even if it's April 19 2013 and you're in Boston. Yet people expend far, far more resources and worry on the latter than the former. It is an interesting quirk of our psychology that we assign far more significance to intentional acts than random ones even when the relative probabilities are so vastly different.

*there's got to be a point where having a fatal heart attack out of the blue becomes more likely than being a fatal automobile accident, and I suppose that's probably before you become "elderly", but I don't know exactly where.

ETA: According to this, in the US car accidents are number 1 if you're 15 to 25, but from 25-45, it's...poisoning. Would not have predicted that; I wonder what's driving that number (drug use is listed separately). After 45 it becomes heart disease and stays that way.

[axordil]

When something bad happens enough to become a statistic, it becomes part of the background noise of the society. That's not saying it's invisible or it can't be changed. It's saying that the acceptable methods for dealing with it are different. It's not eligible for "crisis management" any more.

[halplm]

Actually, suicide just passed car deaths for injury deaths. link

The chance of dying each day is roughly 1.5/million for random causes, but obviously age and health factor into your actual chance of dying in a given day. The way we look at it in decision analysis is assigning a "micromort" to different activities (link to relatively poor wiki description), although I have some issues with that as it's essentially equating money with life decisions... not to mention the differences between accepting the random chances of death as a matter of life vs. actively choosing to increase those chances with dangerous behavior.

The shutdown of Boston was not about safety, or even finding the guys faster. It was about the police seeking vengeance, and the unlawful search of many homes.

And now I've talked about death far more than I want to...

[Dave_LF]

I could have very easily been standing at the very spot where the bombs went off, at the moment they went off. That left me with a pretty visceral connection to the situation.

Ah, but on my less lasto topic, that's also true for any fatal car accident that happens on the roads near your home. And there are lots of those. Yet if you're like most people, that doesn't provoke a visceral reaction.

Do our brains simply decide to discount everything we know about the risks of vehicular travel simply because of the number of times we've done it without negative consequences?

[River]

Do our brains simply decide to discount everything we know about the risks of vehicular travel simply because of the number of times we've done it without negative consequences?

Probably. It might even been an adaptive trait. If you thought about everything that could go wrong every time you went out to hunt a mammoth or some such, you'd end up malnourished and unable to reproduce.

[JewelSong]

Voronwë I wish you would move this to Lastl. I had been thinking of starting a thread there about the marathon bombings....it seems to have started here.

[Dave_LF]

That's not what my question was really supposed to be about--I was just trying to add to the earlier discussion about how people's intuitive perceptions of probability and risk often mesh poorly with reality. If we want to talk about the events in Boston, I'd recommend starting a new thread from scratch.

Or to be more precise, your previous post looks like it would belong there, but I don't think mine do.

[Voronwë the Faithful]

I think I will compromise by splitting this out of the Parlour, but keeping it in Bag End, at least for now.

[Voronwë the Faithful]

That's not what my question was really supposed to be about--I was just trying to add to the earlier discussion about how people's intuitive perceptions of probability and risk often mesh poorly with reality. If we want to talk about the events in Boston, I'd recommend starting a new thread from scratch.

Or to be more precise, your previous post looks like it would belong there, but I don't think mine do.

Actually, even though I left this in Bag End for now, I'm not clear about why you think that a discussion about people's intuitive perceptions of probability would not belong in Lasto?

I'm also not clear on why, when you specifically brought up the attacks in Boston in your initial post, you are surprised that people would focus on that part of the discussion.

[Dave_LF]

Actually, even though I left this in Bag End for now, I'm not clear about why you think that a discussion about people's intuitive perceptions of probability would not belong in Lasto?

Well; I'm always reluctant to start new threads, and there was already a discussion about people's perceptions of probability in that one that seemed like a natural jumping-off point.

I'm also not clear on why, when you specifically brought up the attacks in Boston in your initial post, you are surprised that people would focus on that part of the discussion.

Yeah, you'd think I'd have learned by now.

[Voronwë the Faithful]

On further relection, I am going to send this to Lasto.

[anthriel]

This almost does look like two discussions. Both of them are interesting!

Dave, I happen to be VERY aware of just how dangerous it is to drive. You wait until the little Daveish offspring start to drive; it is never more apparent what a dangerous activity that is, until you watch your kid drive off for the first time.

However, several differences in the level of threat occur to me.

1. It's really tough to function in our country without getting into a moving vehicle at some point. Just the way it is. So in order to get to work, get my hair cut, buy groceries, etc., I need to face the danger of driving. I can wait a few hours in my house, though, if that helps me avoid the danger of being shot by a murderous madman on the loose.

2. At least with driving, SOME of the risk is mitigated by your own choices. Yes, one can always get creamed by a drunken lunatic, totally out of left field, but one can also lessen the more common risks in driving by never driving after drinking, always wearing a seatbelt, choosing less busy times to drive, things like that. A madman on the loose presents a (thankfully rare) danger that you have no way to mitigate, except to do what the police ask you to do as they try to catch him.

3. When I said "intent" earlier, I meant something like: MOST of the people you are driving along side did not get out of bed that morning with the intent to kill fellow drivers. It is a hopeful thing that most people who are driving just want to get safely from A to B, just as you are trying to get safely from A to B. This tragically homicidal pair definitely wanted to kill people, and that puts a different spin on the risk, to me.

[Dave_LF]

On my original subject, it is quite possible that the lockdown saved more lives by reducing traffic than it did by limiting exposure to Dzokhar. I say this as an observation and not as any kind of judgment.

It's really tough to function in our country without getting into a moving vehicle at some point.

That is certainly true and it explains why people are willing to accept the risk, but not why many forget the risk completely. I never drive any substantial distance without pausing to consider the possibility that the trip might kill me, but I think I'm weird that way.

At least with driving, SOME of the risk is mitigated by your own choices.

That's true, but I think there is a tendency to overestimate both how good a driver one is and how much difference that makes. There's really nothing you can do to defend against someone who crosses the center line in a moment of inattention, or who fails to notice the stop sign is 2-way rather than 4. And back to where I started, we could engineer our roads to eliminate those two dangers (I think it's ridiculous that the 2-lane undivided highway still exists in a world where you can be arrested for stepping on a skateboard without a knight's worth of protective gear, for example) and we could do it for a fraction of what we've spent defending against terrorists, but people seem to be ok with 30-40k deaths a year in this case.

This tragically homicidal pair definitely wanted to kill people, and that puts a different spin on the risk, to me.

But why? An x% risk of death is an x% risk of death regardless of whether it's from an accident or a murder, and you're just as dead either way. Why do these two things feel so different?

[JewelSong]

But why? An x% risk of death is an x% risk of death regardless of whether it's from an accident or a murder, and you're just as dead either way. Why do these two things feel so different?

Intent. An accident can happen to anyone at any time. We take reasonable precautions (wear a seat belt, look both ways before we cross the street, use directional signals...) We prepare as best we can and then if something happens - it's a tragic accident. Accidents happen.

Somebody deliberately setting off a bomb in the middle of a festive, happy event like a marathon finish line with the intent of hurting as many people as possible is NOT an accident.

It's not supposed to happen and it shakes us to our core.

And I think you already know this.

[yovargas]

I'm with Dave on this being a weird and interesting bit of human psychology. I'm thinking it's in part due to the simple numbing of repetition. There are places in the world where it's probably more likely to die due to acts of horrific violence then due to car crashes or heart attacks. I wonder if eventually, to the people who live in these areas, these acts of violence become just part of the background noise of life, just another of the risks you gotta face when you get up in the morning but that isn't gonna prevent you from just getting on with your life as best you can.

[Voronwë the Faithful]

I split off the discussion of the Boston bombing and civil rights into a separate thread