Knowing and Making

Despite Chris's warning , I went to Tim Worstall's book launch today. I even bought a copy which I will review on here when I have read it (on the bus tomorrow). But before that, I learned something nice from his answer to an audience question. Apparently, there's a clear relationship between GDP per head and population growth. We already know that people in poorer countries have more children, and the population of those countries grows faster. It seems that there's a measurable cut-off point: at $16,000 per head of GDP, fertility drops to around replacement rate (just over two children per mother) and the population stabilises. Which reminded me of another statistic I read recently: national happiness grows with GDP until a certain point, at which it levels off and people stop getting happier. That level? $17,000 per head *. Now perhaps there's something important in that $1,000 difference, but the two figures are within the margin of error for cross-coun...

This easy-to-mock story about the "tax" on being single is notable in a couple of ways. The first is that - for many - being single is a lifestyle willingly chosen. Perhaps there is a price tag on that choice, but that's different from a tax. £5,000 a year does seem like a lot, but for the luxury of choosing your own holiday destinations, spending all your free time in the way you want to, and designing your living environment entirely to your own tastes, it might be worth it. The second is that the article contains a detailed methodological critique of its own argument. But Stuart Adam, senior research economist at the Institute for Fiscal Studies (IFS), doubts whether the situation is as clearcut as the study presents. "The quarter of a million figure depends first on whether you believe their £5,000 a year finding and I'd need quite a lot of convincing that they'd got their methodology right"... It's even possible that the research is skewe...

No, it's not a Matt Damon film... Richard Wiseman has an interesting experiment over at his blog this week. Have a look at it before you read on - or if you do read my post first, please don't participate in his experiment in case you bias the results. Back now? The experiment combines two really interesting cognitive principles. It's an example of the ultimatum game , a game theory experiment which measures our attitude to fairness. In a rational world, the person making the split should offer their partner just £1 (or even £0) and the partner would have no reason to refuse. In the real world, people do tend to refuse offers less than about £3, and knowing this, the offerer tends to offer an average of about £4.40, with a strong peak on the even split, £5. One thing that interests me is that many of the commenters - even though they are on the blog of a leading popular psychologist - have evidently never heard of the ultimatum game, which is one of the most famo...

I went on a day pass to a new gym today. One of those gyms where the lockers are secured with the members' own padlocks instead of with built-in locks. As expected, the men's changing rooms were full of padlocked lockers. It didn't occur to me that there could be any other way. Turns out, as I discovered later, the women's lockers are not secured at all. Perhaps one locker in the whole room had a padlock. The rest just live on trust. Are men more likely to steal things? Or do men just not trust one another? Who's being irrational here? Readers who attend a gym are invited to report back the results from their own establishment. Just in case, probably best not to say which  gym you're in.