Optimization Metrics

Clara and I have to take a written exam in order to transfer our driver's licenses to Minnesota, so we're studying the Minnesota driver's manual. In the section on crosswalks I found this instruction:

The problem is that you can't leave an intersection both as quickly as possible AND as safely as possible. To leave as quickly as possible would be to sprint the last few yards, raising the chances of tripping and falling. To leave as safely as possible would mean walking slowly and carefully, constantly scanning your surroundings for new dangers, which is not particularly speedy.

       

This curve represents the boundary of your possible choices for how to cross the street. Anywhere inside the curve, you can increase either your speed or your safety, or both. Combinations of speed and safety outside the curve are beyond your ability, such as trying to go both as fast as you can and as safely as you can, the way pedestrians in Minnesota are charged to do.

Of course, no one is really bothered by this in practice; what we actually do is something like "leave the intersection as quickly as possible while still staying reasonably safe."

     

But this is only one way of solving the problem: you could decide instead that you need to leave reasonably quickly and then go as safely as you can at that speed. And either way, the choice of how safe is "reasonably safe" or how quickly is "reasonably quickly" is a little arbitrary.

Anyway, the reason I'm bringing this up is to try to make clear the idea that even if two people value the same things, they might disagree on where to allocate their efforts. This is especially relevant these days, as so many people seem to be talking past each other about what they want for our country. We all want everyone to be better off, but there are many ways to gauge the wellbeing of a population, and you can't optimize them all at the same time. Here are some examples:

• How good the best are. This is how we compare countries in the Olympics, for example.
• How good the average are. This is what we are thinking of when we worry that U.S. students are falling behind those in other countries regarding their math scores, or when we compare different countries based on their GDP per capita.
• How good the total is. If a life is valuable in itself, then all things being equal a larger population is preferable to a smaller one. Measures along these lines include total GDP; policy based on improving that might involve promoting birth rates so we have a larger workforce.
• How bad the worst are. If we want to improve the minimum quality of life in the country, we should concentrate all our efforts on those people who need our aid the most.
• How far apart the best and worst are. If we want everyone to have equal resources, then we should keep on robbing the rich to give to the poor until there's no difference, regardless of where that middle point ends up being.
• How many people fall below a certain threshold. If we've drawn a poverty line and only want to reduce the number of people below it, it's better to adjust handouts so that everyone just makes it above the line, regardless of how much worse off those above the line end up being.

One of these may sound more like your preference than another, even though they're all based on some way of trying to make things better for everyone. It's impossible to optimize with respect to two different metrics at the same time, so you have to choose what to fix at "reasonable" and what you optimize given that, and the choice of "reasonable" is a little arbitrary. So next time you're in an argument with someone, please remember that they might just be trying to optimize according to a slightly different metric, and just because they disagree with you doesn't mean they don't value the same things.

The quest for a dresser

We are making great strides in moving in. We have a books on our shelves, hooks for our keys, and cookies in the cookie jar.

But one of the things that was surprisingly difficult for us was finding a dresser. Most of our furniture came from IKEA, and we were able to check out the various options in the IKEA in Haarlem before we left the Netherlands. That way, we were able to get our new apartment pretty much mapped out before we came.

But while there's much more closet space here than in our place in Leiden, the rooms are more square, so wall space, not floor space, is at a premium. That means using taller, narrower storage whenever possible, so we wanted one of these dressers from IKEA:

But when we looked to see what was available in the states, what we found was more like this:

Where are all the tall, narrow dressers? IKEA isn't offering them anymore in the U.S., the country where they have been sued for the wrongful deaths of several small children who have been crushed in the last few years by chests of drawers tipping over. When we went on our big trip to IKEA last week, signs exhorting customers to affix their furniture to the wall were everywhere.

My knee-jerk reactions:

• "I don't have children! Why shouldn't I be allowed to buy furniture for myself, just because someone else might do so irresponsibly?!"
• "The furniture already comes with brackets to mount it to the wall, and the instructions include that step!" (Sure I've ignored that step in the past—living in a cinderblock dorm room does tend to prevent one from making any kind of hole in the wall—but the consequences of that neglect are my responsibility!)
• "If IKEA really were contrite about these deaths, they'd pull the furniture line everywhere, not just in the one country where they got in trouble!" (It's as if, when they rolled out the slimmer and eco-friendlier KALLAX replacement for their iconic EXPEDIT series, they had only done so in countries that are particularly uppity about environmentalism.)
• "It's not even that big a problem!" I mean, yes, it is an enormous problem if it's your child, and apparently a child in the U.S. is killed once every two weeks by furniture tip-over, which is awful. But given that there are over 21 million children under the age of 5 in the U.S., this works out to a probability of about 99.99938% that your newborn will survive your furniture.  If we were looking at, say, the Netherlands instead of the U.S., at this rate there would be a high probability of no child ever being killed by an IKEA dresser.

But on reflection, maybe discounting the size of the U.S. isn't such a good idea. Maybe a big country, where precedents are set for many at once and where legislative decisions have an exceptionally wide scope, has an extra responsibility to err on the side of safety. Maybe that's why small countries should belong to supranational organizations that impose annoying regulations.

But what does all this mean for us? It means we got our dresser at a thrift store.

What to do when Facebook arguments suck you in

It's happened again: someone's made an inflammatory comment on what's clearly a totally reasonable Facebook post, and you feel your response buzzing in your fingertips. You have two choices: let them have it ("it" being a polite and measured rebuttal, of course) or walk away. The problem is that neither approach is really satisfying.

The problem with engaging

About a decade ago, I used to get in a lot of arguments on the internet. Back then, the debates I dived into were mostly academic, like whether a "neutral" English accent exists, or whether a plane really could take off from a treadmill (the latter, ironically, on the xkcd forums). The amazing thing is that even when you explain to someone that they're wrong, why they're wrong, and how they can be right in the future, they still don't change their mind! They can even seem more convinced of their own position than when you started. So why engage when it's a waste of time?

The problem with ignoring

There's one obvious problem with walking away: someone is still wrong on the internet. But there are subtler problems too. When we pay more attention to content with a worldview similar to our own, algorithms like Facebook's are designed to show us more of that. And when we see less and less of people who disagree with us, it's easier to reduce their views in our minds to simplified caricatures, really held by no reasonable person.

"You don't decide what gets in. And more importantly, you don't actually see what gets edited out."

But we don't even need an algorithm for this to happen. Even if we like having a mixture of perspectives in our lives, a slight desire not to be the odd one out can cause us to naturally segregate ourselves—for an interactive blog post on this idea, see the Parable of the Polygons, an allegory of small individual bias leading to large-scale intolerance.

I wonder whether these effects have to do with the rising levels of political polarization in the U.S. over the last decade.

So what can you do? If ignoring people creates division, and engaging doesn't necessarily help either, what's left?

Listen

It's easy to skim and jump straight into respond-mode. It's harder to pause and ask yourself what's going on in your friend's head—are they feeling angry? Frustrated? Hopeless? Even better: make a guess, and ask if you're right! "It sounds like you're worried that... Is that right?" You may find that there's something else going on than you thought.

And sometimes, showing that you're willing to hear their point of view means that they will spontaneously reciprocate. Since I resolved more often to reflect the desires people were expressing, I was surprised how often I found out they already were considering the viewpoint I'd wanted to share.

But since that doesn't always happen, I like to let go of the idea that victory is making sure your view is the last one heard. If everyone has that goal, no one wins. Instead, reaching a target of just one moment of understanding—even if it's you understanding them—is satisfying and leaves the internet a better place.

If you still feel the need to respond...

Okay, so sometimes you really, really want to make sure your views are also expressed. How can you do that without escalating to frustration?

•  Dress your opponent as Iron Man

A straw man is when you attack a weaker version of someone's argument, so that you can win more easily. But the point is not to win, the point is to be right—so what's the rightest version of what they're saying? Show them that you get it, that they don't need to pull out the rhetoric in case you haven't heard it before.

• Share information, not counterarguments.

After you've shown them that you understand where they're coming from, only then are you in a position to explain why you disagree. But in the spirit of honest communication, don't just pull out the standard rhetoric of your side. Better is to share the facts that caused you to join that side in the first place. After all, that's what convinced you.

I came across a nice summary of this conversation style in a blog post by Eli Dourado on why experts don't always agree:

Someone who is really seeking the truth should be eager to collect new information through listening rather than speaking, construe opposing perspectives in their most favorable light, and offer information of which the other parties are not aware, instead of simply repeating arguments the other side has already heard.

And while you're at it...

Part of the reason these techniques are so effective—listening carefully to the emotions underlying differing viewpoints, rephrasing your opponents' arguments to sound as honestly convincing as possible, and sharing information that might shed light on why we are disagreeing—is that they have the uncomfortable benefit of making it more likely for us to change our own minds in the process. Because we all have to be willing, at least a little bit, to change our minds, if you want our friends to do so too.