harpend comments on Q&A with Harpending and Cochran - Less Wrong

26 Post author: MBlume 10 May 2010 11:01PM

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Comment author: harpend 11 May 2010 03:25:51AM 13 points [-]

That is a big and interesting question. I do not think that evolutionary biology needed more math at all: they would have done better with less I think. The only math needed (so far) in thinking about acceleration is the result that the fixation probability of a new mutant is 1/2N if it is neutral and 2s if it has selective advantage s. The other important equation is that the change in a quantitative trait is the product of the heritability and the selective differential (the difference between the mean of the population and the mean of parents).

The history is that there was a ruckus in the 1960s between the selectionists and the new sect of neutralism, and neutralism more or less won. Selectionists persisted but that literature has a focus on bacteria in chemostats, plants, yeast, and such. Neutralism answered lots of questions and is associated with some lovely math, but as we took it up we (many of us) lost sight of real evolutionary issues.

Milford Wolpoff, in a review of our book in the American Journal of Physical Anthropology points out that his student Dave Frayer collected a lot of data on changes in European skull size and shape that implied very rapid evolution. In other words we "knew it all along" but never paid attention. In fact Cochran and I "knew" it but never put it together with the new findings from SNP chips. John Hawks did, right away.

So fashion rules and we it is difficult to get away from it I suppose.

Comment author: gcochran 12 May 2010 04:23:09AM 13 points [-]

Hawks and I were talking about new genetic studies that showed a surprising number of sweeps, more than you'd expect from the long-term rate of change - and simultaneously noticed that there sure are a lot more people then there used to be - all potential mutants.

As for why someone didn't point this out earlier - say in 1930, when key results were available - I blame bad traditions in biology. Biologists mostly don't believe in theory: even when its predictions come true, they're not impressed.

My advantage, at least in part, comes from have had exactly one biology course in my entire life, which I took in the summer of my freshman year of high school, in a successful effort to avoid dissecting. If I ever write a scientific autobiography, it will be titled "Avoiding the Frog".

Comment author: CarlShulman 12 May 2010 08:22:11PM 2 points [-]

Biologists mostly don't believe in theory: even when its predictions come true, they're not impressed.

Because theory in the field is so often wrong that they treat successes as a stopped clock being right twice a day? Or something more complex?

Comment author: harpend 14 May 2010 02:33:13AM 10 points [-]

I think Greg's 'biologists' are a special subset of biologists. As I see it CP Snow was right about the two cultures. But within science there are also two cultures, one of whom speaks mathematics and the other that speaks organic chemistry. Speaker of organic chemistry share a view that enough lab work and enough data will answer all the questions. They don't need no silly equations.

In our field the folks who speak mathematics tend to view the lab rats as glorified techs. This is certain not right but it is there and leads to a certain amount of mutual disdain.

This kind of mutual disdain is apparently just not there in physics between the theoretical and experimental physics people. I wish evolutionary biology were more like physics.

Comment author: TobyBartels 08 October 2012 08:04:52PM 1 point [-]

It goes further; there are even two cultures of mathematics!

Comment author: gcochran 14 May 2010 06:59:07AM *  7 points [-]

There are sub-patterns. There are facts about natural selection that every plant geneticist knows that few human geneticists will accept without a fight. I mean, really, Henry, when a prominent human geneticist says " You don't really believe that bit about lactase persistence being selected, do you?" , or when someone even more famous asks "So why would there be more mutations in a bigger population?" - their minds ain't right.

Comment author: NancyLebovitz 14 May 2010 09:31:57AM 2 points [-]

There are facts about natural selection that every plant geneticist knows that few human geneticists will accept without a fight.

Could you expand on that?