How to Spot a Psychopath

A reader writes:

Something has been bugging me for a while, but I didn't want to ask anyone in case it sounded racist, which it isn't, because some of my best friends are members of the inferior races which Asians like me will soon enslave.

Internet anonymity lets me ask YOU, though:

Why do old black people so often not look as old as identically old white people?

I'm asking now because I've seen a few excellent examples in just the last few days.

I was watching Joe Morton in Eureka, and he looks EXACTLY THE SAME as he did in Terminator 2, 20 years earlier.

And look at this guy! He just died at age 75, but in the picture of him performing a year ago he could be 50, or 40 even.

And then I watched a recent Daily Show where George Clinton did a walk-on, he's 70 but looked 50, tops.

And the flipside: Just now Reddit brings me a young basketballer who only needed some fake white hair and beard and bang, plausible old black man!

(OK, there was some latex work there too. But you can't see that clearly even in HD, and he still looks old.)

I know black people don't actually LIVE any longer, quite the opposite here in the States, but looking young your whole life has to be some consolation. How/why does it happen?!

Z

I have heard this phenomenon described as "black don't crack", but I, like you, don't know whether it's safe for non-black people to call it that in company.

(This whole situation, especially in the USA, seems to have taken a terribly wrong turn at some point after Blazing Saddles.)

In the case of people in TV and movies this phenomenon is, of course, at least partially the result of makeup, lighting and plastic surgery. But you're right when you say that it happens in "real life" too.

The reason is actually quite simple.

When you get older, your skin loses elasticity and you get more wrinkly. The principal factor in the visibility of wrinkles is light, or more precisely shadow. Wrinkle-hills cast shadows in wrinkle-valleys, and those shadows play a big part in making a face look old.

If you've got pale skin, wrinkle-shadows show up very clearly. But the darker your skin is, the closer to the shadow shade it all is naturally, and the less obvious are the wrinkle-shadows, and the less old you look. That's really all there is to it.

Rub your face with lampblack and, no matter what colour your skin was before, it'll now be so dark that wrinkle-shadows will be almost invisible. Do the same thing with titanium dioxide powder and every tiny line will stand out clearly, unless you're only illuminated by a light right next to the viewer.

(This is why the built-in flash of a compact camera tends to make everybody's face look flat and weird - but not wrinkly! A photographer may use a "beauty dish" to add a controlled amount of this effect to a portrait.)

This same phenomenon can be seen in some peculiar places. Take the moon, for instance.

A full moon is much more than twice as bright as a half moon, because of what's called the "opposition effect". The effect is partly caused by the retroreflective qualities of lunar regolith - it tends to reflect light back the way it came. There may be some quantum weirdness involved too. But the opposition effect occurs mainly because the lunar surface is very uneven, thanks to meteorite impacts and no erosive forces. So there are lots and lots of shadows when the moon is illuminated from the side from our point of view, making it half-full, but there are almost no shadows at all when it's full, and illuminated by the sun looking over the earth's shoulder, as it were.

(The albedo of the moon is surprisingly low - it's about as dark as an asphalt road. It seems so brilliant in the night sky because it's illuminated by direct sunlight, not because it's actually the pale grey it seems to be when compared with the surrounding dark sky.)

The "black don't crack" phenomenon is one small part of numerous more-or-less-racist theories that explain one or another kind of physical advantage that dark people are supposed to have over pale people.

One of the more popular of these theories is that black slaves were literally bred to be stronger and healthier, since there wasn't much of a market for longsighted asthmatic cotton-pickers. Whether the claim is that this breeding was forced by slave-owners, or was just a result of brutal natural selection that caused weak slaves to often die before reproducing, though, it's pretty clear from genetics and genealogy that it actually didn't happen.

There is evidence for something like this in some situations. It's hardly surprising, for instance, that a number of successful very-long-distance runners have come from cultures where, for centuries or even millennia, being good at cursorial or persistence hunting has been a way to get more wives and offspring.

Even in these situations, though, there are many confounding factors. Running is something almost anybody can do, almost anywhere. It requires no expensive equipment or special facilities. So poor countries, regardless of culture, produce more runners than they do, say, golf or polo players. (And every now and then along comes a little white guy who's accustomed to spending days on end rounding up sheep, on foot.) For the same reason, you don't see many bobsled teams from countries where it doesn't snow.

(While I'm digressing, here's a note even less relevant to the original question: Because I'm in Australia, thedailyshow.com doesn't want to show me that George Clinton video. I just get a "Sorry, this video is unavailable from your location" error. If you have the same problem, you can solve it with the Modify Headers Firefox extension, which lets your browser say it's asking for the page on behalf of a US IP address. Find instructions on how to do this here.)

Psycho Science is a regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.