Thursday, October 15, 2009

Let’s celebrate human genetic diversity

By Bruce Lahn
Department of Human Genetics, University of Chicago

Lanny Ebenstein
Department of Economics,University of California at Santa Barbara

Nature 461, 726-728 (8 October 2009) | doi:10.1038/461726a; Published online 7 October 2009

Science is finding evidence of genetic diversity among groups of people as well as among individuals. This discovery should be embraced, not feared, say Bruce T. Lahn and Lanny Ebenstein.

A growing body of data is revealing the nature of human genetic diversity at increasingly finer resolution. It is now recognized that despite the high degree of genetic similarities that bind humanity together as a species, considerable diversity exists at both individual and group levels (see box, page 728). The biological significance of these variations remains to be explored fully. But enough evidence has come to the fore to warrant the question: what if scientific data ultimately demonstrate that genetically based biological variation exists at non-trivial levels not only among individuals but also among groups? In our view, the scientific community and society at large are ill-prepared for such a possibility. We need a moral response to this question that is robust irrespective of what research uncovers about human diversity. Here, we argue for the moral position that genetic diversity, from within or among groups, should be embraced and celebrated as one of humanity’s chief assets.

The current moral position is a sort of ‘biological egalitarianism’. This dominant position emerged in recent decades largely to correct grave historical injustices, including genocide that were committed with the support of pseudo scientific understandings of group diversity. The racial-hygiene theory promoted by German geneticists Fritz Lenz, Eugene Fischer and others during the Nazi era is one notorious example of such pseudoscience. Biological egalitarianism is the view that no or almost no meaningful genetically based biological differences exist among human groups, with the exception of a few superficial traits such as skin colour. Proponents of this view seem to hope that, by promoting biological sameness, discrimination against groups or individuals will become groundless.

We believe that this position, although well intentioned, is illogical and even dangerous, as it implies that if significant group diversity were established, discrimination might thereby be justified. We reject this position. Equality of opportunity and respect for human dignity should be humankind’s common aspirations, notwithstanding human differences no matter how big or small. We also think that biological egalitarianism may not remain viable in light of the growing body of empirical data.

Many people may acknowledge the possibility of genetic diversity at the group level, but see it as a threat to social cohesion. Some scholars have even called for a halt to research into the topic or sensitive aspects of it, because of potential misuse of the information. Others will ask: if information on group diversity can be misused, why not just focus on individual differences and ignore any group variation? We strongly affirm that society must guard vigilantly against any misuse of genetic information, but we also believe that the best defence is to take a positive attitude towards diversity, including that at the group level. We argue for our position from two perspectives: first, that the understanding of group diversity can benefit research and medicine, and second, that human genetic diversity as a whole, including group diversity, greatly enriches our species.

Wednesday, October 14, 2009

The Young and the Neuro

By David Brooks
New York Times
October 12, 2009

...In 2001, an Internet search of the phrase “social cognitive neuroscience” yielded 53 hits. Now you get more than a million on Google. Young scholars have been drawn to this field from psychology, economics, political science and beyond in the hopes that by looking into the brain they can help settle some old arguments about how people interact.

These people study the way biology, in the form of genes, influences behavior. But they’re also trying to understand the complementary process of how social behavior changes biology. Matthew Lieberman of U.C.L.A. is doing research into what happens in the brain when people are persuaded by an argument.

Keely Muscatell, one of his doctoral students, and others presented a study in which they showed people from various social strata some images of menacing faces. People whose parents had low social status exhibited more activation in the amygdala (the busy little part of the brain involved in fear and emotion) than people from high-status families.

Mina Cikara of Princeton and others scanned the brains of Yankee and Red Sox fans as they watched baseball highlights. Neither reacted much to an Orioles-Blue Jays game, but when they saw their own team doing well, brain regions called the ventral striatum and nucleus accumbens were activated. This is a look at how tribal dominance struggles get processed inside.....

Jonathan B. Freeman of Tufts and others peered into the reward centers of the brain such as the caudate nucleus. They found that among Americans, that region was likely to be activated by dominant behavior, whereas among Japanese, it was more likely to be activated by subordinate behavior — the same region rewarding different patterns of behavior depending on culture.

All of these studies are baby steps in a long conversation, and young academics are properly circumspect about drawing broad conclusions. But eventually their work could give us a clearer picture of what we mean by fuzzy words like ‘culture.’ It could also fill a hole in our understanding of ourselves. Economists, political scientists and policy makers treat humans as ultrarational creatures because they can’t define and systematize the emotions. This work is getting us closer to that....

Many of the studies presented here concerned the way we divide people by in-group and out-group categories in as little as 170 milliseconds. The anterior cingulate cortices in American and Chinese brains activate when people see members of their own group endure pain, but they do so at much lower levels when they see members of another group enduring it. These effects may form the basis of prejudice.

But a study by Saaid A. Mendoza and David M. Amodio of New York University showed that if you give people a strategy, such as reminding them to be racially fair, it is possible to counteract those perceptions. People feel disgust toward dehumanized groups, but a study by Claire Hoogendoorn, Elizabeth Phelps and others at N.Y.U. suggests it is possible to lower disgust and the accompanying insula activity through cognitive behavioral therapy.

In other words, consciousness is too slow to see what happens inside, but it is possible to change the lenses through which we unconsciously construe the world.

Since I’m not an academic, I’m free to speculate that this work will someday give us new categories, which will replace misleading categories like ‘emotion’ and ‘reason.’ I suspect that the work will take us beyond the obsession with I.Q. and other conscious capacities and give us a firmer understanding of motivation, equilibrium, sensitivity and other unconscious capacities.

The hard sciences are interpenetrating the social sciences. This isn’t dehumanizing. It shines attention on the things poets have traditionally cared about: the power of human attachments. It may even help policy wonks someday see people as they really are.