Tuesday 2 December 2014

Rate of decline in intelligence from mutation accumulation - first estimate

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In a new paper in Personality and Individual Differences, Michael Woodley has made the first estimate of the rate of decline in intelligence which would be expected due to mutation accumulation, and puts it at about 0.8 IQ points per decade

http://iqpersonalitygenius.blogspot.co.uk/2014/12/michael-woodley-estimates-rate-of.html

He also calculates the rate of decline due to selection - i.e. the higher fertility of less intelligent people, and vice versa - and puts that at about 0.4 IQ points per decade.

And at the end he estimates the magnitude of decline in average intelligence due to recent migration and immigration as about 0.3 IQ points per decade.

Combining all these, leads to an overall current rate of intelligence decline of about 1.5 IQ points per decade - which is a lot!

To this must be added the effect of an ageing population (estimate pending...).

This is what we find!

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6 comments:

Joel E. said...

But we also need to account for population growth. There are many more of us today, so there should be many more >130 IQ people out there. So while per-capita issues (number of doctors, lawyers) may suffer, absolute measures (numbers of interesting novels, breakthroughs) could well be going up.

For the second number, all of the biological issues may be swamped by any change in the allocation of intelligent people to various tasks. How many intelligent people today are doing something useless instead of something globally useful? How many are doing something per-capita useful? Etc.

Bruce Charlton said...

@Joel - These processes have been going on for 150plus years, so I think the compensatory effect of larger European populations was a factor back then - but as the processes leading to decline have accumulated then the effect of population increase would have been overwhelmed - and the population stopped increasing a few decades ago.

As for your second point - I agree. This is part of the big problem of 'not even trying'. For example, the push to allocate vital jobs to people on the basis that they are women, or minorities is the act of a society which has given-up trying to actually perform functions - a society which sees jobs as sugar plums rather than as things which need to be done as well as possible.

Part of this is to be indifferent to what people actually do.

In the mid 1970s there was a lot of public discourse (stimulated by EF Schumacher's work) about the importance of *real* work, doing useful things, and about the moral and psychological effects of work - this topic has evaporated, and the whole subject is met with cynical careerism or cynical parasitism (which amount to the same thing).

Joel E. said...

My own belief is that the misallocation of human genius is so extreme, that in those rare historical instances when that his been fixed for one reason or another, we will often have works from one city, from just one century, that will outshine most civilizations.

William Zeitler said...

Studies have shown that the productivity difference between a 'good' programmer and a 'great' programmer is an order of magnitude -- that is, the great programmer can cut about 10 times as much production code in the same amount of time as the 'good'/average one. Does compensation anywhere correspond to that? It does in some companies -- e.g. Microsoft (at least in their golden days) and now Google. As a super-productive programmer myself, I have also been in corporate environments where to anyone above my immediate manager, programmers were all viewed as interchangeable. Thus, hiring decisions in good times, and who got laid off in difficult ones, came down to metrics like race and gender, and not productivity. I'm one of those capable guys that got sick of it (and I have plenty of company) and now makes a happy living on the fringes of society as a musician. I just can't bring myself to use my abilities to prop up a fundamentally corrupt state of affairs any more.

Jonathan C said...

I like the quote, "the push to allocate vital jobs to people on the basis that they are women or minorities is the act of a society which has given-up trying to actually perform functions - a society which sees jobs as sugar plums rather than as things which need to be done as well as possible." It's a really succinct statement of something that's clearly true, but I hadn't crystallized it quite that way. Into my quotes file it goes.

Bruce Charlton said...

@Jonathan - I realize this comment has been appended to the wrong post. I need to fix the grammar of that quote!