18/06/2008

Yet Another Post Featuring Me in a Pub. Coincidence?

Yay again! After possibly having discovered a new bias, I've now coined a new phrase. It is digital thinking. Heck, we could even call this yet another bias. I'm starting this one with an anecdote, so bear with me.

About eighteen months back, a friend of mine had a birthday party which she had decided to do during the day, rather than at nighttime. But of course, arriving at noon is not a good reason not to have any alcohol, so when I left at seven or eight, I was feeling a bit tipsy. As we say in Germany, half-drunk is wasted money. Well, technically, I hadn't spent any money, but you get the idea: I frequented a local pub.

Now, here's a recommendation: If two young men approach you in a pub and ask: "Where would you put yourself politically, on the left or on the right?", you want to get out of that conversation as quickly as possible. I didn't. I said something like: "Neither. I try to make up my mind issue-by-issue. Sometimes I end up on the left, sometimes on the right, and sometimes in between." Which, of course, prompted the first bloke to ask on which issue I would place myself on the right, and I replied that criminals must be punished harshly.

So we ventured into a conversation on crime. Maybe I was in a bit of a provocative mood; at any rate, I mentioned that there are genetic influences on criminal behaviour. That idea was new to them, to say the least. I had been trying to explain the difference between the statements "That's 50% genetic" and "50% of the variance is explained by genes" for about a minute as the second bloke exclaimed: "Well, those are technicalities! What you're saying is that rehabilitation can't work!"

Erm, no. In fact, I know that some rehabilitation programmes work somewhat. The second person commited a fallacy that is rather common, as pointed out by Steven Pinker in The Blank Slate: Once you say there are genetic influences on something, people take this to mean that something is genetically determined. (In the realm of behaviour and psychology, nothing has ever been found to be genetically determined, and I would be surprised if this would ever change.)

But that's just one instance of a more common problem: Digital Thinking. In digital systems, it's either 0 or 1. Likewise, people (as I'm not the first person to point out) have a strong tendency to see life as though things were lights that can be switched on or off, but can't be dampened. Things are either black or white. I'm not saying of couse, that people can't see shades of grey - that would be ridiculous - but rather that they are not very good at it. That's not too surprising given that seeing shades of grey is more cognitively taxing than seeing things just as black and white.

If you don't believe me, consider that even scientists - not the stupidest people on earth - think like that. Imagine a study being published in a journal that finds a positive association between X and Y, p = 0.06. Yawn! Not statistically significant. Now imagine that later a correction is published which says: "Sorry, our point estimates were correct, but there was a typo: The p-value is actually 0.04." Kawoom! The noteworthiness of the result suddenly skyrockets, despite the fact that the difference between 0.06 and 0.04 is trivial.

What really shocked those two young men in the pub, however, was when I told them I was a sociologist. As a friend of mine later put it, I, of all people, should really know better.

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