Bryan Caplan  

Behaviorial Geneticists versus Policy Implications

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In most disciplines, experts oversell their ability to give useful policy advice.  In behavioral genetics, however, experts strangely undersell their ability to give useful policy advice.  Here's a striking passage from Plomin, DeFries, McClearn, and McGuffin's leading behavioral genetics textbook:
The idea of genetic contribution to g has produced controversy in the media, especially following the 1994 publication of The Bell Curve by Herrnstein and Murray (1994).  In fact, these authors scarcely touched on genetics and did not view genetic evidence as crucial to their arguments.  In the first half of the book, they showed, like many other studies, that g is related to educational and social outcomes.  In the second half, however, they attempted to argue that certain conservative policies follow from the findings.  But, as discussed in Chapter 18, public policy never necessarily follows from scientific findings; and on the basis of the same studies, it would be possible to present arguments that are the opposite of those of Herrnstein and Murray.
Logically speaking, the textbook is right.  The germ theory of disease doesn't necessarily imply that we should wash our hands more.  A misanthrope could "on the basis of the same studies" argue against hand-washing, because he wants people to suffer and die.

My complaint: Plomin et al are setting up a straw man.  Policy analysts almost never argue that public policies "necessarily follow" from scientific findings.  Instead, they argue that public policies follow from scientific findings combined with some moral principles.  They usually try, moreover, to reason from relatively uncontroversial moral principles like cost-benefit analysis in order to persuade a broad audience. 

The interesting question, then, isn't "Do the scientific findings in this book necessarily imply any policies?"  The answer to that question is "no" for all sciences and all policies.  The interesting question for a behavioral genetics textbook is rather, "Do the scientific findings in this book combined with the moral principles that policy analysts routinely use imply any policies?"

The answer to the latter question is definitely "yes."  I've discussed an obvious example before: When you ignore IQ, you overstate the marginal effect of other variables.  The result: Cost-benefit analysis that ignores IQ makes educational investments look more favorable than they really are.  Herrnstein and Murray weren't just arguing for "certain conservative policies"; they were arguing for those policies using the standard rules of the policy analysis game.

So why are behavioral geneticists so eager to downplay the practical relevance of their field?  The most plausible explanation is that these scientists already have enough trouble with political correctness.  They don't want to amplify their public relations problem by pointing out that their science undermines a bunch of popular, feel-good policies.

Critics of behavioral genetics are prone to hyperbole, but they do have good reason to fear this science.  It really does undermine a lot of their sacred cows.  Example: If differences in talent - not differences in opportunities - explain the inter-generational income correlation, people with normal values will conclude that a lot of redistribution is unjustified.  "Giving everyone a chance to realize his potential," isn't the only rationale for redistribution, but it is an important one.  If people admitted that family environment has little effect on economic success in our society, there is every reason to expect a decline in support for redistributive policies.

Admittedly, the critics of behavioral genetics could reply, "We want our current level of redistribution (or more!) no matter what the science says."  But they don't want to say that, because it makes them sound like dogmatic ideologues.  The upshot: Behavioral genetics makes its politically-correct critics angry because the scientists are putting the politically correct in an awkward position: Deny the science, abandon some of their favorite policies, or sound like dogmatic ideologues.  It's no wonder that they're angry - and no wonder that they deny the science.  They're not just making the best of a bad situation; they're also getting a little revenge on the researchers responsible for their unpleasant predicament.



TRACKBACKS (2 to date)
TrackBack URL: http://econlog.econlib.org/mt/mt-tb.cgi/1938
The author at Fahreunblog in a related article titled La medusa PC pietrifica gli studiosi writes:
    Osservazione: Conclusione Lo studioso terrorizzato si contraddice di continuo cercando di far dimenticare al più presto la sua scoperta. In questo caso: impegnarsi molto nella cura dei bimbi non produce risultati apprezzabili... senonchè dobbiamo [Tracked on June 10, 2009 2:22 PM]
The author at corrupt.org: Remaking Modern Society in a related article titled What Stupidity Can Science Kill? writes:
    Behavioral genetics is a science which seems to undermine the roots of many core leftist beliefs - so should conservatives pour their money and energy into supporting behavioral genetics research instead of politics? As Bryan Caplan summarizes: So why ar [Tracked on June 12, 2009 5:06 AM]
COMMENTS (13 to date)
fundamentalist writes:

Without a doubt, the emphasis on spending on education completely ignores the IQ effect, but that benefits socialists.

L for Liberty writes:

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Daniel Lurker writes:

Is cost-benefit analysis really "relatively uncontroversial"? in the context of persuading a broad audience? Health care, HOT lanes, outsourcing .... the public seems unpersuaded.

And I can empathize with geneticists humility - if they were to discuss the importance of their findings openly it might undermine public perception of the credibility of their research. Once they go from innocent scientists behind the scenes to suggesting applications, policy analysts and voters stop seeing them as benign nerds and quickly envisage an army of Frankensteins. Then, even the information that geneticists could previously discuss safely becomes viewed with heightened suspicion.

Climate change is a very rough analogy - whenever a scientist on either side comes out with evidence they are attacked politically.

I'm with you all the way, but unsure if there's a pragmatic way for anyone to persuade the public to give up so many sacred cows.

Dan Weber writes:

If I were in favor of redistribution, couldn't I just say "those people aren't actually working harder: they just have better genes, and it's not fair to us"? Like Mankiw's height tax.

Trevor H writes:

Bryan - to you last paragraph, I think the fear is not that dogmatic idealism will be revealed, rather that it is moral principles known to be controversial. Most people prefer to stick with the non-controversial principles knowing that if their true principles were revealed (from each according to his ability, to each according to his need) that many supporters of their policies would defect.

hacs writes:

I have many difficulties with some theoretical concepts derived from "experiments". For example, a social scientist or a behavioral geneticist formulate an IQ theory. So, as any good scientist he/she will test his/her theory against data. A common approach is to collect data about the financial success of a sample, at last, it is considered a "good" proxy for IQ. Suppose this test corroborate that theory and, as usual, it is used as a frame to formulate sound public policies. Is it make sense?

Not necessarily because of a simple problem, circular logic. For example, if the population of which the used sample was drawn rewards a set of values and behaviors because of tradition, dogma, prejudice, or any other objective or subjective reasons (many of them invisible and unprintable), degrees of financial success in that population will reflect too degrees of fit to that set of values and behaviors, consequently, that IQ theory too. Public policies framed by that theory will reinforce that set of values and behaviors on that population, increasing the effects of them, and so on.

I prefer to deal with those theories very conservatively, facing them as statistical conjectures momentarily undeniable, putting them in a long run and collective perspective of Science (regret is not a good alternative when people lives are in question). That is, those conjectures need to surpass the difficult robustness test of multigenerational and multicultural reproducibility.

Dr. T writes:

I don't see how behavioral genetics matters in the current political and educational climate. We will just continue our decades-long trend towards one-size-fits-all education. The knowledge about IQ and learning, intelligence and the environment, the preferred learning modes of each child, and the best ways to teach each child is largely unused in our schools. Instead, we park 32 eight-year-old kids onto chairs so a teacher can talk at them for hours straight, we drug the 20% of boys who fidget, and we wonder why most kids hate school and why the dropout rate is 30%.

Kevembuangga writes:

I see no reason for the "critics of behavioral genetics" to be really worried, democracy being the rule of the most numerous and the gifted people being a minority democracy will take care of the well being of the marching morons.
At the cost of a little cognitive dissonance of course.

Greg writes:

Re Kevembuangga: Yes, the marching morons do much better in this society than the gifted. Clearly, they have the vast majority of the wealth and personal freedom. I think you're confusing fiction with reality.

sfer writes:

Harrison Bergeron isn't a story about progressive income tax.

Josh writes:

Peter Singer on this dilema:

"Darwinian left would not:

• Deny the existence of a human nature, nor insist that human nature is inherently good, nor that it is infinitely malleable;

• Expect to end all conflict and strife between human beings, whether by political revolution, social change, or better education;

• Assume that all inequalities are due to discrimination, prejudice, oppression or social conditioning. Some will be, but this cannot be assumed in every case;

A Darwinian left would:

• Accept that there is such a thing as human nature, and seek to find out more about it, so that policies can be grounded on the best available evidence of what human beings are like;

• Reject any inference from what is 'natural' to what is 'right';

• Expect that, under different social and economic systems, many people will act competitively in order to enhance their own status, gain a position of power, and/or advance their interests and those of their kin;

• Expect that, regardless of the social and economic system in which they live, most people will respond positively to genuine opportunities to enter into mutually beneficial forms of cooperation;

• Promote structures that foster cooperation rather than competition, and attempt to channel competition into socially desirable ends;

• Recognise that the way in which we exploit nonhuman animals is a legacy of a pre-Darwinian past that exaggerated the gulf between humans and other animals, and therefore work towards a higher moral status for nonhuman animals, and a less anthropocentric view of our dominance over nature;

• Stand by the traditional values of the left by being on the side of the weak, poor and oppressed, but think very carefully about what social and economic changes will really work to benefit them.

In some ways, this is a sharply deflated vision of the left, its Utopian ideas replaced by a coolly realistic view of what can be achieved. That is, I think, the best we can do today — and it is still a much more positive view than that which many on the left have assumed to be implied in a Darwinian understanding of human nature.

If we take a much longer-term perspective, there may be a prospect for restoring more far-reaching ambitions of change. We do not know to what extent our capacity to reason can, in the long run, take us beyond the conventional Darwinian constraints on the degree of altruism that a society may be able to foster. We are reasoning beings. In other works I have likened reason to an escalator, in that, once we start reasoning, we may be compelled to follow a chain of argument to a conclusion that we did not anticipate when we began. Reason provides us with the capacity to recognise that each of us is simply one being among others, all of whom have wants and needs that matter to them, as our needs and wants matter to us. Can that insight ever overcome the pull of other elements in our evolved nature that act against the idea of an impartial concern for all of our fellow humans, or, better still, for all sentient beings?

No less a champion of Darwinian thought than Richard Dawkins holds out the prospect of 'deliberately cultivating and nurturing pure, disinterested altruism -something that has no place in nature, something that has never existed before in the whole history of the world'. Although 'We are built as gene machines,' he tells us, 'we have the power to turn against our creators'. There is an important truth here. We are the first generation to understand not only that we have evolved, but also the mechanisms by which we have evolved and how this evolutionary heritage influences our behaviour."

http://www.utilitarian.net/singer/by/1999----02.htm

Kevembuangga writes:

@sfer
Harrison Bergeron isn't a story about progressive income tax.

There is much worse than progressive income tax, this is the kind of things I was alluding to.

Alex Harris writes:

Might part of the explanation for behavior geneticists' humility be the historical antecedents of attempts to link genetics with policies (notably the eugenics movement)?

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