mattnewport comments on The President's Council of Advisors on Science and Technology is soliciting ideas - Less Wrong

9 Post author: Kevin 12 July 2010 11:41PM

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Comment author: mattnewport 13 July 2010 06:01:21PM 1 point [-]

Do you know of any evidence suggesting strong heritability of rationality?

Comment deleted 13 July 2010 06:21:21PM [-]
Comment author: mattnewport 13 July 2010 06:27:33PM 2 points [-]

I'm skeptical of a strong heritability for rationality independent of IQ. Your original statement suggested to me that you knew of stronger evidence than 'most things are heritable'. If you don't know of any such evidence I'm inclined to remain firmly on the fence.

Comment author: NancyLebovitz 13 July 2010 11:03:27PM 2 points [-]

Have you read The Millionaire Next Door? The book is about people of very ordinary intelligence who are more rational about money than many smarter people.

Comment author: mattnewport 13 July 2010 11:51:53PM 2 points [-]

I haven't read it but I don't think this kind of example talks directly to the question of whether rationality is a strongly heritable trait independent of IQ. My current hypothesis (not strongly held or supported by large amounts of evidence) is that rationality is more a learned skill or habit of thinking which will tend to correlate with IQ (because higher IQ people will learn it easier/faster and apply it better) but that some high IQ people have failed to learn it and some lower IQ people have become quite good at it.

Examples of lower IQ people who are more rational than higher IQ people do not on their own help to distinguish whether rationality is a separately heritable trait from IQ or a learned habit of thinking.

I would not be hugely surprised if certain big 5 personality traits or other potentially heritable personality traits made people more inclined to learn rational thinking which might provide an indirect basis for heritability of rationality.

Comment author: NancyLebovitz 14 July 2010 01:18:14AM 0 points [-]

I wasn't reading carefully, so I just offered evidence that rationality is somewhat independent of IQ.

Comment author: SilasBarta 13 July 2010 11:15:47PM 1 point [-]

Didn't the people in that book get rich by saving a lot and investing aggressively for the long term?

How's that strategy working out?

Comment author: NancyLebovitz 13 July 2010 11:19:26PM 2 points [-]

I don't know of any follow-ups.

They invested conservatively, not aggressively. I expect they're better off than people who got heavily into debt, but probably not as well off as some people who were insiders enough to not lose too much when they made bad investments for other people.

Comment author: SilasBarta 14 July 2010 01:44:02PM *  0 points [-]

I meant aggressively in the sense of well-diversified and stock-heavy (hence the "long-term" bit). If they got rich off of bond interest, well, it wasn't investment acumen that explains their success, but a) raw earning power, and b) not spending it all.

"Assume a high income" is not all that helpful.

Comment author: NancyLebovitz 14 July 2010 11:22:43PM 0 points [-]

Unfortunately, exactly what they invested in wasn't something I was very sensitive to, and I don't remember it.

Generally, they had fairly ordinary incomes, and they invested in things which were considered low-risk at the time. A fair number of them had real estate in the sense of owning car dealerships (used car lots?), with the land under the business being a large part of their wealth.

They disliked spending money. It was common for them to be men whose wives made a full-time job of running the household cheaply. (There was a later book called The Millionaire Woman Next Door.)

Comment deleted 13 July 2010 06:43:15PM [-]
Comment author: Hook 13 July 2010 07:41:21PM 1 point [-]

For heritability, I think rationality is closer to reading than it is to intelligence.

Comment author: NancyLebovitz 13 July 2010 11:12:59PM 0 points [-]

How heritable is reading?

Comment author: Hook 14 July 2010 12:43:44PM 2 points [-]

For the time being, I'll just consider literacy as a binary quality, leaving aside differences in ability. In developed countries, with literacy rates around 99%, literacy is probably some what heritable because that <1% cannot read because of some sort of learning defect with a heritable component.

In Mail, with a 26.2% literacy rate, literacy is not very heritable. The illiterate there are a consequence of lack of educational opportunities. I think that the situation we are in regarding the phenotype of "rational" is closer to the Mali scenario rather than the developed world scenario.

Comment author: mattnewport 13 July 2010 07:11:09PM 1 point [-]

You mean in general or for rationality in particular? Lots of things are heritable, to varying (and often disputed) extents. I tend to think genetic factors are often underestimated when explaining human variability. I'm not familiar enough with the evidence for heritability of other high level cognitive abilities to make a very good estimate for the heritability of rationality however.

I've just bought What Intelligence Tests Miss for my Kindle after reading the article series here. As I said, I'm skeptical that rationality as an independent factor from IQ is strongly heritable but I'm open to evidence to the contrary which is why I was curious if you had any.

Comment deleted 13 July 2010 07:19:29PM *  [-]
Comment author: mattnewport 13 July 2010 08:19:15PM *  2 points [-]

You should still have a prior. "I don't have enough detailed info" is not an excuse for not having a prior.

No, it's not, but I think it's a reasonable excuse for not having a more specific prior than 'low and uncertain'. Being more specific in my prior would not be very useful without being more specific about what exactly the question is. I sometimes see a tendency here to overconfidence in estimates simply because a bunch of rather arbitrary priors have been multiplied together and produced a comfortingly precise number.

Why not just take the probability distribution of heritability coefficients for traits-in-general as your prior?

I don't know what it is. I suspect it is not a well established piece of information. I'm not convinced that heritability for 'traits-in-general' is a good basis for rationality in particular. Do you have a reference for a good estimate for this distribution?

Comment deleted 13 July 2010 08:30:07PM *  [-]
Comment author: mattnewport 13 July 2010 08:53:06PM *  3 points [-]

I never qualified 'low' with 'very' or 'really'. If numbers make you feel better 'low' means roughly 1-10% probability. I find it a little backwards when someone focuses so much on precisely quantifying an estimate like this before the exact question is even clarified. I see it a lot from non-technical managers as a programmer.

I started this thread by asking for the information you were using to arrive at your (implied) high confidence in a genetic basis for rationality. There's been several recent articles about What Intelligence Tests Miss and I haven't started reading it yet (though it is now sitting on my Kindle) so I was already thinking about whether rationality as a separate trait from IQ is a distinct and measurable trait. I haven't seen enough evidence yet to convince me that it is so your implication that it is and is strongly heritable made me wonder if you were privy to some information that I didn't know.

While assigning numerical probabilities to priors and doing some math can be useful for certain problems I don't think it is necessarily the best starting point when investigating complex issues like this with actual human brains rather than ideal Bayesian reasoning agents. I'm still in data gathering mode at the moment and don't see a great benefit to throwing out exact priors as a badge of Bayesian honor.

Comment deleted 13 July 2010 09:10:36PM [-]
Comment author: Vladimir_Nesov 13 July 2010 09:22:37PM *  0 points [-]

You can apply laws of probability to intuitive notions of plausibility as well (and some informal arguments won't be valid if they violate these laws, like both X and ~X being unexpected). Specific numbers don't have to be thought up to do that.