This morning I sat on a panel for medical students; the subject was obesity. Nationally, as anyone who hasn’t been hiding under a rock knows, the picture is not pretty-in fact it’s pretty ugly. By the standard definition, obesity means a Body Mass Index (BMI; weight in kilos over height in meters squared) above 30, and in about 15 years starting in 1990 we went from 22 percent to 33 percent obese.

Now, I don’t care what you call it or where you want to draw the line. Pick any BMI number and you’ll see more Americans above it every year. This includes children and teens, who are showing up in pediatricians’ offices in growing numbers with Type II diabetes, which used to be called "adult-onset." In some practices there are more of them than there are of Type I, once called childhood diabetes.

Don’t want to call it an epidemic of obesity? Fine. Endemic, pervasive, skyrocketing, steeply increasing, whatever. Anyone who’s telling these kids that it’s okay and they should feed good about their bodies is doing them and the country a huge disservice. They are headed for diabetes, heart disease, colon cancer, arthritis, and many other conditions in record number. Help them with their body image issues, but don’t tell them it’s fine to be fat.

But why this trend? Isn’t it maladaptive? In evolutionary terms, the answer is simple. Not just for millions but for hundreds of millions of years our ancestors were selected to store fat during times of abundance. That way, you could survive lean times. Trouble is, now there’s no end to abundance.

Among the Bushmen of Botswana, who I lived with for two years, and other hunter-gatherers, there was no starvation but there was also no obesity. Foods were harder to get, eat, and digest, and they maintained a high level of aerobic and muscular fitness just because of activity in the food quest. Compared to our diet , theirs was much higher in fiber and much lower in refined carbs, saturated fat, and salt. Children were always outdoors and active.

Our genes and bodies evolved in that context, and they just can’t handle what we do to them now.

Culture matters, of course. My colleague Peter Brown and I many years ago looked at the ideal of beauty in cultures throughout the anthropological record. Plumpness is the ideal in over 80 percent. Look at paintings by Rubens, Titian, and Tintoretto, and you’ll see the women who were considered the greatest beauties of their time. Other eras have prized less plump women, but few thin enough to make Playboy, much less Vogue.

Slim was the ideal in a few cultures, very fat in none. Pleasantly plump but not obese was the goal in most, and the extra fat those beauties stored held just about the extra energy they would have needed to get through a pregnancy and a couple of years of lactation. In other words, they were beautiful because they could make and nourish a baby.

In some cultures in the past, frank obesity was evidently valued. Carvings like the "Venuses" of the late Stone Age looked like women with very high BMIs, possibly also pregnant. Some cultures in Africa had fattening huts for adolescent girls to prepare them for marriage. In many cultures you displayed your wealth and status by showing you could put on surplus fat. But it stopped with pleasantly plump, probably because serious signs of ill health became evident when you went further.

But we live in the Supersize Culture, which is producing a legion of boys and girls, men and women, who are far fatter than the plumpness that used to be (and in much of the world still is) the norm. Yet ironically ours is a culture with a cosmetic ideal that’s uniquely thin. It’s not a health ideal; mortality is lowest at a BMI of 22 or 23, which you would never see in a typical fashion ad. And at its worst the ideal leads to anorexia or bulimia.

Those are bad, sometimes deadly disorders, but the implications for the population are far more dire at the other end of the BMI spectrum. And like most bad things, the trend is worst for the poor. Our society consigns the poor to put on weight by making it hard and expensive to get good food and easy and cheap to get junk.

The trend affects Blacks (especially women) more than Whites, in part because of culture but mainly because of access. You can’t find fresh fruit and vegetables in the inner city, and you don’t want your kids playing outside on streets rife with drugs and gunfire. You’re struggling to keep body and soul together, so when your kid sits for hours watching TV and eating snacks, you’ve got bigger worries than BMI.

But it’s up to us as a society to recognize that there is more going on here than lack of will power. The human species was set up to store fat whenever possible and to resist weight loss with many fail-safe appetite mechanisms. And for very good evolutionary reasons, it’s even harder to keep weight off than to lose it.

So we’d better rethink our laws, school food policies, farm subsidies, educational programs, and information campaigns before we have to change our name to Homo lipidens.

Note: By invitation, I’ve started a blog on the Psychology Today website , and my latest post can be read there or here, although different comments may be  posted there.

Most psychologists don’t like human nature, or at least not the idea of it. Clinicians, life coaches, and corporate motivators dislike it because it implies unchangeability. Anyone who took college psychology knows how to modify behavior, from direct instruction to manipulative advertising.

And then, what fool surveying the huge variety of human personalities, needs, and tastes would dream of trying to characterize all that as one thing? Well, some fool might, but not the philosophers, evolutionists, historians and political leaders who have long used the phrase. They’ve always meant something complex, varied, and big-but not limitless.

 Barack Obama, for instance. He talked about it in his Nobel Prize acceptance speech, a stark contrast to his famous speech in Cairo in the first spring of his presidency, when he reached out to the world. In Oslo he stepped up to accept the peace prize, and said, "[W]ar is sometimes necessary, and war is at some level an expression of human feelings." He quoted John F. Kennedy, who said we should "’focus on a more practical, more attainable peace, based not on a sudden revolution in human nature but on a gradual evolution in human institutions.’"

Leaders have long invoked human nature, and they don’t always accentuate the negative. Thomas Jefferson, in an early draft of the Declaration of Independence, denounced the British slave trade, saying the King "has waged cruel war against human nature itself , violating its most sacred rights of life and liberty in the persons of a distant people who never offended him."

Ironic, of course, since Jefferson owned slaves, but a clear statement that slavery is contrary to human nature. In 1859, in his famous Cooper Union speech, Lincoln echoed the sentiment: "Human action can be modified to some extent, but human nature cannot be changed . There is a judgment and a feeling against slavery in this nation…" Four years later, amid a horrendous war, he signed the Emancipation Proclamation.

George Washington was no less a human nature theorist. As the Articles of Confederation stumbled, he wrote John Jay, the future Chief Justice, "We have probably had too good an opinion of human nature in forming our confederation," and stressed the need for a "coercive" government power, which emerged in the Constitution.

But a hallmark of that second try was the separation and balance of powers, the direct result of the founders’ dim view of human nature . Power corrupts because human nature yields to temptation. Institutions must pit one corrupt group against another; power can only be checked by the countervailing power-lust of other humans.

In fact the Constitution was a kind of monograph on human nature, and at the same time one of the greatest of all inventions-a well-oiled, robust, intricate machine designed to keep the worst parts of human nature in check.

The founders were also influenced by the ideas of Benjamin Rush, the colonies’ leading physician and psychiatrist. He wrote of "the anatomy of mind," and it included variation. In a model that Jefferson explicitly accepted, Whig and Tory-what we would now call liberal and conservative-were innate dispositions that could neither persuade each other nor be reconciled. Thus the machine of government had to allow them to grind at each other in controlled wars of words so they would not fall to civil wars of steel.

But again, it’s not just about the dark side. Here’s what Winston Churchill said at MIT a few years after the worst war in history:

"Scientists should never underrate the deep-seated qualities of human nature and how, repressed in one direction they will certainly break out in another. The genus homo if I may display my Latin - is a tough creature who has travelled here by a very long road. His nature has been shaped and his virtues ingrained by many millions of years of struggle, fear and pain, and his spirit has, from the earliest dawn of history, shown itself upon occasion capable of mounting to the sublime, far above material conditions or mortal terrors."

Churchill invokes not just human nature but the "many millions of years" behind it. Obama the liberal and Churchill the conservative agree: Human nature has a dark side but also a spirit that can mount to the sublime. It embraces a broad but definable range of people, and there will always be a struggle not just among, but within each of us, as our ideal of the good contends with the selfish need to survive.

Without both, natural selection would long ago have consigned us to the trash heap of evolutionary history. This struggle, between our worst and best inclinations, is permanently part of us. Human nature is real, and it will not change soon.

For more on the founders’ ideas about human nature, see "Darwin’s Truth, Jefferson’s Vision."

Note: By invitation, I’ve started a blog on the Psychology Today website , and my latest post can be read there or here, although different (and likely more numerous) comments will be  posted there.

Note: By invitation, I’ve started a blog on the Psychology Today website, and my latest post can be read there or here, although different (and likely more numerous) comments will be  posted there. This entry resembles and updates one I posted here in March 2009, which was followed by an interesting exchange on “insatiable widows” and other cross-cultural myths.

We hear a lot about sex differences, and arguments rage over which are real. Evolutionary theorists weigh in about why this or that difference should be expected, while some anthropologists say cultures vary so much that generalizations are folly. But of all Darwinian predictions about la différence, few are as logical as the one about sex differences in sexuality. Here’s why.

Women risk so much more in any coupling that natural selection should have made them wary; those who were not took reckless risks. Males have a lot less to lose, so women should be more reluctant and choosy. Or, as anthropologist Donald Symons said, most cultures have understood that sex is something that women have and men want.An exaggeration, certainly. Women who didn’t want it at all, ever, didn’t leave many offspring. But between the sexes all is relative, and women have hand. Their reproductive power sets a limit, their big investment is at stake every time, and a uterus is a hugely valuable thing.

In the anthropological record about two thirds of societies made men offer wealth or service to their brides’ families; this “brideprice” had no exact counterpart on the other side-dowries, practiced in about three percent of cultures, were traditionally from the bride’s family to the couple, and occurred in highly stratified societies where there was severe competition for the highest-status men.

But neither evolutionary theory nor cross-cultural data can prove a sex difference. Here’s where psychological studies come in, and two reviews by Roy F. Baumeister and his colleagues are relevant. The first, co-authored by Kathleen Catanese and Kathleen Vohs, asked, “Is there a gender difference in sex drive?” and reviewed hundreds of studies. The answer is an unequivocal yes.

Men think about sex more often than women, experience sexual arousal twice as often, have more frequent and varied sexual fantasies about more different partners, masturbate much more frequently, want more partners in the future, and expect sex earlier in a relationship-the actual timing being highly correlated with women’s expectations, not at all with men’s. Virtually all sexual practices, “normal” or otherwise, are more likely to be desired by men.

Women tend to be satisfied with the amount of sex in their marriages but have husbands who want considerably more, even after many years together. Men are twice as likely to initiate sex. Complaints of low sexual desire and difficulty achieving orgasm are far more common in women than men, and the most common sexual problem in young men is premature ejaculation, a sort of excessive eagerness. Or if you invoke “nervousness,” then it often seems to have opposite effects on the two sexes.

Now take the “opposite” sex out of the picture. That should clarify things, especially in a world of male dominance and coercion. Well, gay men have far more sex partners than lesbians, and are more likely to cheat on a long-term partner and less likely to abstain for long periods. Among Catholic clergy, women are more successful in achieving and maintaining celibacy than men.

Now-classic research by Russell Clark III and Elaine Hatfield was published in 1989 after a decade of rejections. Women and men of average attractiveness approached college students of the other sex and asked if they would go to bed with them; 77 percent of the men said yes, 100 percent of the women said no. Two recent replication studies in different countries had less extreme results: women said yes 6 percent and 4 percent of the time (the first study was of women only; the second had a male “yes” rate of 45 percent). Sex with a stranger is the ultimate evolutionary litmus test, and the difference is huge.

In 2004 Baumeister and Vohs looked at sexual economics, with few surprises. Female sex workers routinely charge men for sex; their clients are almost never women. Men sell sex, but-despite the dramatic exceptions-their clients are almost all male. In heterosexual relationships, women speak of “giving” their virginity as a gift, men do not.

What of those who can have a surfeit? Attractive female sports stars resent and fend off sexual attention; males tend to welcome it and take advantage, up to thousands of partners. Even in our liberated culture, men tend to pay for dates during courtship, and there is no “gentlemen’s night” at the local club where women pay the cover charge and men get in for free.

Darwinian predictions may be neat, but theory doesn’t make them true; only the long slog of research can do that. In this case, Symons was basically right. He also noted that for a spell in the sixties and seventies men almost had women convinced that they had as much to gain in sex as any man.

Luckily for our daughters, this trick worked only transiently, and neither sexual revolution, contraception, nor women’s growing economic power appear to have changed the underlying reality.

To say that Craig Venter’s latest contribution is garnering hype would be one of the understatements of the year.  The paper, whose title begins “Creation of a Bacterial Cell…” was published in the print version of Science on July 2—Daniel Gibson was the first of many authors, Venter the last—but it had already appeared online on May 20 and generated a lot of comment, not least of all by Venter himself.

As he said in his May 21 press conference, “We’re here today to announce the first synthetic cell,” and, “This is the first self-replicating species that we’ve had on the planet whose parent is a computer.”

Well, not exactly.

What they actually did was take the sequence of a bacterial cell’s genome, synthesize it from DNA bases, attach some code that says “I’m man-made” (to avoid misleading future scientists, in case it should go wild), and insert that synthesized (really re-synthesized) genome into a cell from a closely related bacterial species that had been surgically relieved of its own.

Result: a nature-made bacterial cell powered by a human-made genome which was basically a copy of a nature-made genome–a little less overwhelming than the hype.

It actually began with noisy anticipation not long after Venter’s group (alongside that of Francis Collins) shared credit for the first draft sequence of the human genome. Venter soon announced that the creation of life was his next goal, and by February 14, 2003, a news article in Science was headlined this way:

“Tinker, Tailor: Can Venter Stitch Together a Genome from Scratch?” and, “J. Craig Venter plans to create microbes to cure the world’s environmental woes. Whether he can even partially succeed is an open question.” It still is.

At that time he thought he would achieve the first step—“creating a synthetic genome that, when inserted into a cell, can live and replicate”—in three years. It took seven. Some of the unexpected obstacles included complexity and unpredictability of even a bacterial genome, the absence of knowledge of the functions of many parts, their highly specific and unknown effects on each other, and incompatability of genomic parts that at first might appear interchangeable.

So the first step took seven years, and life was not really synthesized, just reprogrammed with a somewhat altered genome.

Some find this game-changing; the distinguished bioethicist Arthur Kaplan wrote in late May, “Venter’s achievement would seem to extinguish the argument that life requires a special force or power to exist. In my view, this makes it one of the most important scientific achievements in the history of mankind.”

Whew. Fortunately, this effusive appraisal was part of a symposium in Nature, where some scientists were slightly less gee-whiz:

“Relax,” wrote Jim Collins, a biomedical engineer at Boston University. “The work…is an important advance in our ability to re-engineer organisms. It does not represent the making of new life from scratch.”

Martin Fusseneger, a professor of biotechnology at ETH Zurich, said, “It is a technical advance, not a conceptual one.” George Church, a geneticist at the Harvard Medical School, said, “The semi-synthetic mycobacterium is not changed from the wild state in any fundamental sense. Printing out a copy of an ancient text isn’t the same as understanding the language.”

And Steen Rasmussen, a physicist at the University of Southern Denmark, said, “the radical ‘top-down’ genetic engineering that Venter’s team has done does not quite constitute a ‘synthetic cell’ by my definition…The top-down community seeks to rewrite the genetics program running on the ‘hardware’ of the modern cell…Bottom-up researchers, such as myself, aim to assemble life—including the hardware and the program.”

I’m on record as an admirer of Venter (unlike some academics), and if his entrepreneurial spirit gets out of hand a bit sometimes, I don’t mind. “Partial genetic reprogramming of a bacterial cell” would have been more circumspect than announcing the “creation” of a cell. I am sure Dr. Venter did not choose the word “creation,” so often associated with God, by accident.

Nevertheless, this is indeed a critical first step toward the ultimate goal not of playing God, but of making helpful organisms—ones that can eat huge oilspills like the one in the Gulf of Mexico, and then quietly die away; or mine metal ores, replacing horrendous forms of human effort; or compete with and outfox microbes that kill us.

A new responsibility? Sure. But also a welcome one. Less than the hype, but still something for Craig and his colleagues to write home about.

As for faith not everyone’s is easily challenged. I remember talking as a boy with a friend who had become an ultra-Orthodox Jew. The subject was the then-recent amino acid synthesis in the lab under conditions meant to simulate the origin of life. Suppose, I asked, this work went on and life itself was really synthesized? My friend didn’t miss a beat: “I would say, God did it again!”

The comments on my last posting, “We Can’t All Be Mozart,” were so thoughtful and interesting that I decided to post another blog on this. To my general claim that innate talent matters, I opposed a fact close to home that seems to contradict it: I have two grown daughters, one a slightly-older stepdaughter (Logan) with no genetic relationship to her sister (Sarah), who have both been  successful in contemporary dance. None of their four parents or eight grandparents showed any noteworthy talent in dance.

Ann Cale Kruger, a developmental psychologist and Logan’s mom, pointed out that they both, “had the same inspiring and demanding teacher,” who “guided, cajoled, dared, and challenged” them to develop their talents, and that the interplay of guidance and gifts is uniquely human. I completely agree, but that teacher, gifted and no doubt once well-guided herself, did the same for many other young people. Some of them—an improbably high proportion, I would guess—became successful dancers, but the great majority did not.

Travis wrote very cogently that evolution left us with a variety of skills and inclinations in the human population, and that “Every so often…people like Mozart or Einstein are put in precisely the appropriate environment for their genes to flourish…Meanwhile, the vast majority of us are stuck trying to fit our squares into circles.” I agree with these points, and with his conclusion that each of us just has to keep trying to find that match.

Freda praised her parents, who “poured their energies and resources into providing the widest possible range of opportunities (thus environments?)…that we would one day find our unique ways of succeeding. Like your daughter, my sister and my chosen paths of terrestrial ecologist and physician/musician, respectively, were not quite expected paths following the shoes of a businessman and statistician/linguist-turned-housewife. Nonetheless, it makes me wonder if subtle characteristics that drive our approach to life and share with our parents - whether genetically determined or taught through environment/circumstance - led us down our chosen paths.”

My answer would be that those subtle characteristics are passed down through both genes and environment. I would add that tossing up the genes of a businessman and a statistician/linguist-turned-housewife and seeing them fall out into a future terrestrial ecologist and a future physician/musician is not very surprising. Consider the talents, skills, inclinations and temperaments Freda and her sister must have shared with their parents to have the careers they do, and you’ll see what I mean.

But I am very far from belittling the power of the environment. It’s surprising to see the unrelated daughters of two professors become professional dancers, and less surprising to see an ecologist and a physician come from Freda’s parents, but in none of those cases would the results be remotely possible without enormous environmental input.

Not surprisingly, this is what the research shows.

A 2009 study by Anna Vinkhuyzen and her colleagues at VU Amsterdam (the Free University of Amsterdam), looking at 1,685 twin pairs, found substantial genetic contributions to both superior ability and exceptional talent. For example, their Table 6 shows much higher correlations for exceptional talent between identical (MZ, monozygotic) and non-identical (DZ, dizogotic) twins.

Yet these authors conclude “that practice is indispensable…high heritability does not mean environmental influences to be unimportant. To reach exceptional levels of ability, deliberate practice is indispensable even for people with a genetic predisposition to develop a talent.” Other studies show that practice—on a musical instrument, for example—changes the brain in proportion to the number of hours practiced.

So I agree with Freda’s idea that “’impressionable’ neural circuits in a child” will be subject to environmental shaping, but I don’t see why they should be “random.” Genes guide brain wiring to some extent before birth, and if they didn’t we wouldn’t be born with working brains at all. This applies to universal core features of the brain, and I don’t see why it wouldn’t also apply to some individual differences—independently of and prior to different experiences and training.

Clearly these two kinds of factors work best when added to and interacting with each other. It will still be a long time before we understand exactly how this happens, but in the meantime it will be best to keep our minds open to both of them. Open-mindedness, we know, is partly innate, but fortunately we also know it can be cultivated and taught.

A comment by Jack Davis on my last blog entry leads me to write something about talent, genes, environment, and how we succeed. Jack asks about a new book by David Shenk, The Genius in All of Us: Why Everything You’ve Been Told About Genetics, Talent, and IQ Is Wrong. I can’t comment on the book itself, having not yet read it, but I visited the Amazon.com page, watched the video, read the excerpts and the interview with the author, and read some of the commentary.

This is an area of science I have been following and thinking about all my life. I just published a 960 page book (The Evolution of Childhood, Harvard University Press) about the interplay of biology (including genetics) and environment (including learning, culture and other influences). While I always want to learn more, I’m not optimistic that Shenk’s book will supply much information that I don’t already have.

For example, the chapter provided by Amazon in pdf form (Chapter 2) contains good basic information about how genes work. It quotes Charles Murray and Richard Herrnstein’s 1994 book The Bell Curve unfavorably, as I do, and it quotes leading scientists like Michael Meaney, Victor McKusick, and Patrick Bateson, all favorably, as I also do.

On pages 23-24 Shenk recounts a 1958 rat study that I also like a lot; in fact, the second chart is one I have been drawing on blackboards since 1974, when I first taught human behavioral biology–and when there still really were blackboards. It shows that you can’t predict what will happen when you continue to enrich the environment, and that the impact of genes depends on the environment.

But I have to say that this is not exactly news, and that the subtitle of the book tells you a lot about what is going on here: Why Everything You’ve Been Told About Genetics, Talent, and IQ Is Wrong. This is not just a bold statement, as Shenk tells the interviewer, it is the setting up of a straw man. The straw man says that it’s all in the genes and you as a poor, put-upon, gullible reader believe that, so someone has to come along and tell you that the environment matters too.

In fairness to Shenk, authors rarely control titles, and of course our current cultural context matters. Back in 1974, when I first drew that chart on the board and asked my students to explain it, you couldn’t say much at all about genetic influences on behavior without being pilloried. Sandra Scarr was spat upon on a visit to a leading university and E.O. Wilson had ice-water poured on him on the platform at a national scientific meeting (“Professor Wilson, you’re all wet!” was the clever contribution of the pourers.)

Why? Because they both said that genes had some influence on behavior. Both had also written about the power of the environment, but that didn’t matter; they gave some power to genes, and that was all their opponents needed to know.

That course I first taught in 1974 grew into the first edition of The Tangled Wing: Biological Constraints on the Human Spirit, published in 1982. I wasn’t doused or spat upon, but some reviews included accusations of genetic determinism, which anyone who had actually read the book would know were false. In fact I hemmed and hawed so extensively that when I rewrote the book twenty years later I had to purge it of countless apologies-in-passing.

By then the culture had changed. Genetic and evolutionary explanations had caught on much faster than I expected. A turning point for me came when Newsweek, in a special issue on children, had the headline, “Scientists Estimate That Genes Determine Only About 50 Percent of a Child’s Personality,” spread across the top of two pages. The year was 1997, and genes had become so accepted that “only about 50 percent” was considered news.

And it still is. The Amazon page for Shenk’s new book has an invited review by a distinguished psychiatrist, Louann Brizendine, who writes in praising the book, “Ambition, persistence, and self-discipline are not just products of genes, but can be shaped by nurture and environment. Certainly it is important to have good genes, but that determines at most only 50 percent of your talent.”

My reaction to “at most only 50 percent” of talent in 2010 is like my reaction to “only about 50 percent” of personality in 1997: Wow! I remember 1974 and 1982, when you would be slapped down hard for saying 10 or 20 percent!

But: I do understand the dangers in today’s gene-soaked culture. I endorse the need to encourage every child to be every thing she can be. I did that with my children, and I do it every time a struggling student comes into my office. I have yet to tell a single one “you can’t do this,” and I won’t.

Not to brag, but this past weekend I saw my daughter perform a dance duet, which she and her partner had choreographed, onstage at the Kennedy Center in Washington, in the National College Dance Festival. The  odd thing is, she was the second of our daughters to dance at the Kennedy Center. And the  odd thing about that: they are not genetic related, nor is any of their four parents a dancer.

Logan Kruger, my stepdaughter, who is 19 months older, is a brilliant dancer who performed there last year with Shen Wei Dance arts (she’s now with the Limón Dance Company). When our families began to blend a decade ago, Sarah Konner (then 13) began to follow in Logan’s footsteps. Logan, who had been dancing all her life, achieved an amazing blend of skill and artistry. Sarah progressed rapidly and achieved a lot in both but leaned toward choreography as well as dance.

Imagine if I or her stepmother had told her that the chances of her succeeding as Logan had were very low? Both of them showed talent, both showed intense motivation and discipline, both put in their ten thousand hours and more of practice, both succeeded against long odds.

But I’ve lived long enough to see some young people fail at some things no matter how hard they tried. Genes do play a role, albeit a complex one, and “you can be anything you want to be” can become a way of blaming the child. Still, perspiration is good. We can’t all be Mozart, but we can be the best version of ourselves.

Finally, as I pointed out in my last blog, let’s not forget that we are in a new era in another way: Finding a clear genetic influence can be the first step in finding an environmental fix—a diet, a medication, a specific learning program. Today genes are part of the solution, not just part of the problem.

Over the past few weeks two articles have shown the promise and the difficulty of studying brain genes. One appears in the New England Journal of Medicine of May 20, and zeroes in magnificently on a gene for Tourette’s Syndrome.

That would be “a” gene, not “the” gene, since there isn’t and won’t be a single-gene explanation for this complex disorder. It begins in childhood, and can range from mild occasional tics to disabling stereotyped behaviors like throwing the arms and legs around in contorted movements. Vocal tics are part of the diagnosis, and these can take the form of repeated and involuntary yelling of socially prohibited utterances like curse-words or even racial epithets. Needless to say, all this has long interested people curious about how the brain produces language.

One curious thing about Tourette’s is that focused activity can abolish the tics. Oliver Sacks famously described a surgeon who had wild tics in department meetings (he had to sit on the floor in a corner to avoid hurting himself and others) but had an absolutely steady hand in the operating theater. Another oddity is the recent proposal, by my colleague at Emory Shlomit Ritz Finkelstein, that the involuntary utterances may be different in different cultures; as long as they give offense in a given social surround, they’ll apparently do the job that the Tourette’s brain is seeking.

We’ve known for decades that the problem involves a circuit from cerebral cortex to basal ganglia to thalamus and back to cortex, possibly also involving the limbic system and frontal lobes, and that part of the circuit uses the neurotransmitter dopamine, because drugs that block dopamine help. But the new research reveals something else entirely.

A team based at Yale found a family in which the father and all eight of his children, but not their mother, have Tourette’s. This had to be the signature of simple Mendelian inheritance of a single gene, most likely a dominant gene on a non-sex chromosome. The chances were still very low that all eight kids would have it, but they did.

In the gene-sequencing, a small segment of chromosome 15 was flagged and studied more closely, and the team narrowed in on the gene for an enzyme called histidine decarboxylase (HDC). This is the rate-limiting enzyme in the brain’s manufacture of another neurotransmitter, histamine.

More zeroing in put the finger on the 951st DNA base in the coding part of the gene. Here a simple, single-base mutation substituted an A (adenine) for a G (guanine). The father and every affected child had the substitution. The mother and her unaffected blood relatives did not.

This is gorgeous. This is high school genetics, or maybe today middle school, not to do but to understand. So simple; so elegant; so revealing.

More sleuthing: the team studied the proteins made by the normal and abnormal genes. The result of the base substitution was a premature stop signal that dwarfed the protein from a normal length of 662 amino acids to a mere 316. This abnormal protein was the dominant gene product that prevented normal histamine production in the patients’ brains.

Not only that, but lab studies had shown that neurons projecting from the rear end of the hypothalamus, using histamine, end on the circuit already implicated in Tourette’s. And finally, experiments show that mice deficient in HDC, and therefore in histamine, have stereotyped rearing, sniffing, and biting–thought to be a plausible model for human tics.

Now, it’s true that this family represents only a teensy fraction of people affected by Tourette’s, and few other cases will fit this model. So why am I so excited?

It’s not just the elegance of the science, although I love that. It’s that there are already drugs under study in humans that specifically stimulate histamine receptors of they type that are now implicated in Tourette’s. This study may bring a new treatment closer.

So where’s the down side? Well, it’s not in this line of work, but in another study, showing the disappointment so common in genetic studies.

A group studying identical twins discordant for multiple sclerosis—one twin has MS, the other doesn’t, and they’re past the age when it would have appeared if both were going to get it—published their results in Nature on April 29th. The cover dramatically showed the silhouettes of a woman in a wheelchair and another woman standing beside her. But the research report inside showed…nothing.

MS disables people by stripping their neurons of myelin, the fatty sheath that makes axon cables work well. The idea was that completely sequencing the genomes of the twins might show mutations that one had suffered but the other had not. If it had, the team could have gone on to do what the Tourette’s team did, perhaps pinpointing a new clue to future treatments.

No such luck. Very thorough study showed no genetic differences, and less thorough backup studies of two other discordant twin pairs likewise came up empty-handed.

It’s still interesting, because it means that in such cases some environmental causes were responsible, not genes. But we already knew that unknown environmental factors play a role in MS, and this research gives no further clues to what they are.

So you win some, you lose some. But both these strategies for finding genetic needles in haystacks are very valid, and there will be more good news from this kind of research.

Since I criticized President Obama’s speech last year in Cairo (and even “rewrote” it) and later pointed out the names and deeds of those who did not get the Nobel Peace Prize because he did, I think it’s only fair that I resume this blog after a long hiatus by writing about his Nobel Prize acceptance speech in December.

I have to say that it stunned me. Although he had to address the controversy over his prize and nod toward those who had been passed over, he was exceptionally gracious and eloquent in doing this:

“Compared to some of the giants of history who have received this prize - Schweitzer and King; Marshall and Mandela - my accomplishments are slight. And then there are the men and women around the world who have been jailed and beaten in the pursuit of justice; those who toil in humanitarian organizations to relieve suffering; the unrecognized millions whose quiet acts of courage and compassion inspire even the most hardened of cynics. I cannot argue with those who find these men and women . . . to be far more deserving of this honor than I.”

He also acknowledged that as the Commander in Chief of the world’s most powerful armed forces he was conducting two protracted wars even as he was being deemed the year’s most effective peacemaker. But that too wasn’t what surprised me. It was that he used his Nobel Peace Prize platform to articulate a brief for war, and that in doing so he appealed to arguments those of us in behavioral biology have made for many years:

“War, in one form or another, appeared with the first man. At the dawn of history, its morality was not questioned; it was simply a fact, like drought or disease - the manner in which tribes and then civilizations sought power and settled their differences.”

He went on to try to define a “just war” and to insist, quite rightly, that it is possible to conduct a war according to ethical rules, although, “For most of history, . . . just war was rarely observed.” It was surely not accidental that he began by saying that war “appeared with the first man,” since the nature of war rests with and arises mainly from men: “Terrorism has long been a tactic, but modern technology allows a few small men with outsized rage to murder innocents on a horrific scale.”

But where he sounded most Darwinian was in talking about the future: “We must begin by acknowledging the hard truth that we will not eradicate violent conflict in our lifetimes. There will be times when nations - acting individually or in concert - will find the use of force not only necessary but morally justified.”

His is an optimistic nature, but he clearly felt compelled to make a dark prediction. And in contrast to his speech last year in Cairo, in Oslo he fully acknowledged the inescapable constraints of his position:

“[A]s a head of state sworn to protect and defend my nation . . . I face the world as it is, and cannot stand idle in the face of threats to the American people. For make no mistake: evil does exist in the world. A non-violent movement could not have halted Hitler’s armies. Negotiations cannot convince al Qaeda’s leaders to lay down their arms. To say that force is sometimes necessary is not a call to cynicism - it is a recognition of history; the imperfections of man and the limits of reason.”

No Darwinian philosopher could have said this better. And no conservative Republican could have been more persuasive in defense of his country’s role: “The United States of America has helped underwrite global security for more than six decades with the blood of our citizens and the strength of our arms.”

He went on even more clearly, “war is sometimes necessary, and war is at some level an expression of human feelings.” And he quoted a predecessor, John F. Kennedy, who urged a “’focus on a more practical, more attainable peace, based not on a sudden revolution in human nature but on a gradual evolution in human institutions.’”

Mr. Obama devoted the rest of his speech to ways to promote that evolution, and in doing so invoked another human trait, “the one rule that lies at the heart of every major religion . . . that we do unto others as we would have them do unto us. Adhering to this law of love has always been the core struggle of human nature. We are fallible . . . But we do not have to think that human nature is perfect for us to still believe that the human condition can be perfected.”

And, nearing the end, he quoted the man who did the most to make his presidency possible, Martin Luther King, Jr.: “’I refuse to accept the idea that the “isness” of man’s present nature makes him morally incapable of reaching up for the eternal “oughtness” that forever confronts him.’”

All three leaders—Kennedy, King, and now Obama—accepted the hard fact that our hope for a human future different from the past must begin with human nature as it is. The future cannot change that nature, it can only shape evolving institutions of democracy, diplomacy, and law that use what we know about our nature to render its consequences less ominous and tragic.

For a few years in the ‘70s and ‘80s, I worked with her and Jane Lancaster, a distinguished anthropologist now at the University of New Mexico and editor of the journal Human Nature, on a committee of the Social Science Research Council, and both of them affected my thinking about gender.

But Alice was much more senior, and because she was a founder of NOW, she had impeccable feminist credentials. She was brilliant, tough-minded, compassionate, competitive, and maternal all at once, and I learned a lot from her.

I already considered myself a feminist, but being oriented to the biological bases of behavior, I could not accept the kind of feminism that insisted essentially on sameness—on the claim that there are no fundamental psychological differences between men and women, and that all purported differences were invented by a male chauvinist culture.

Neither, it turned out, could Alice. She belonged to a long tradition of what are now called difference feminists, who believe that women must have equal rights and power not just in spite of but in part because of the fundamental differences. Others in this camp include Carol Gilligan, the famous psychologist who argued that women carry out moral reasoning with a greater emphasis on care, and make different judgments as a result.

My encounters with Alice made me realize that I was a difference feminist too. I had gone to demonstrations in the ‘60s and ‘70s to support women’s rights, but I had also written that sex differences in physical aggression are a cross-cultural universal for biological reasons. Therefore, I argued, the world will be safer when women have as much or more power than men.

I don’t say that Alice would support this line of reasoning, but she did tell her fellow feminists and the professional world of sociology that men and women are fundamentally different. Her courage in doing that drew considerable fire at the time, and the message I took from her counsel was that difference is perfectly compatible with equality.

The charge of our committee was to consider the implications of biology for parenting and offspring development, and we had a series of meetings with experts who tried to shed light on this newly born, or perhaps newly reborn subject. Alice and Jane helped edit a series of books on various aspects of the committee’s work and I was proud to contribute to a couple of them.

But Alice’s presence and leadership was key. On the one hand, conservatives resented her because she championed the rights of women, and some men in academia who considered themselves liberals couldn’t abide how outspoken she was about the domination of universities by men. On the other hand, she never thought that men and women are the same.

Although she may not have said it in so many words, I learned from her something I think is still true: that the most underrepresented minority in the academic world is mothers. Alice in her writings and speeches emphasized that women’s lives have a different time course than men’s, and that it is essential for not only colleges and universities but all institutions in our society to recognize that.

In part because of her arguments, Hillary Clinton, Sandra Day O’Connor, Ruth Ginsberg, and many others were able to be mothers and also to lead at the highest levels, because it wasn’t expected that their resumés would look just like men’s.

Alice and her husband, Peter Rossi, conducted one of the only studies of behavior and the menstrual cycle that included men as control subjects. I recall two findings: first, weekends made a heck of a bigger impact on women’s behavior than the menstrual cycle did. Second, men had the same average number of days per month of moodiness and discomfort–they just came randomly, while the women’s bad days were tied to menses.

I still quote this study to my students. I have to tell them that once upon a time menstruation was used as an excuse to keep women out of certain professions, since their behavior became supposedly erratic a few days a month. The reason my students don’t know this is that Alice Rossi and a handful of other women erased that stupid idea from our culture’s consciousness before most of them were born.

So I explain, and then I ask them: Would you rather have your airplane or your country piloted by someone who has a few days a month of moodiness and discomfort that arrive without warning, or someone with the same number of bad days that come around like clockwork? Even with freshmen, I don’t have to wait for an answer.

But in the same wise and effective lifetime, Alice managed to argue and teach that men and women can be both different and equal, and that in discussing gender, biology does not have to be banned from our vocabulary. She was much admired, is fondly remembered, and will be missed.

I said to Monica, “Well, you probably use the word ‘myself,’ what do you mean?” She said, “It’s the part of me that’s unique, that no one else has. It’s also my consciousness, my private thoughts, my identity.” I thought that was about as good a definition as I could offer, although I added that the self is what you alone see, a kind of parallax shift from what others see and even measure, but what subjectivity allows only you to access.

Nevertheless, as Leopold Bloom muses in Joyce’s Ulysses, we do try rather desperately to “see ourselves as others see us”—we are intersubjective from childhood–and so every new outside measure of who we are has the power to change that parallax view.

As to my notion of “the new biology,” it has to include at least four things.

First, especially in this year of Darwin’s birthday and anniversary, it has to include the new evolutionary biology.

Second, it has to involve the new genomics, including personal genomics and ethnic tracing.

Third, it must take account of the revolution in brain imaging.

And, finally, it has to acknowledge the transformative and accelerating power of enhancement drugs.

So please indulge me while I try to figure out how these four kinds of facts might, for better and for worse, be changing our ineffable—our nearly unutterable–subjectivities.

From the time I ceased to be religious at 17, evolution has been my overarching narrative of origins, and to say it affects my sense of myself is putting it mildly. At the time of a famous debate between Thomas Huxley and the Bishop of Worcester, the bishop’s wife is supposed to have said, “Descended from apes! My dear, let us hope it is not so, but if it is, let us pray that it does not become generally known.”

This marvelous reflection declares a profound fear of the consequences of this particular piece of objective knowledge for the self writ large, the selves, as it were, of millions. I agree with her intuition that the consequences are momentous, but not that they are dire. Her first fond hope, alas, was not realized; it is indeed true. But her second hope, a prayer, remains alive, at least in the United States, where more than half of our fellow citizens reject this important fact.

But what’s new?

Too many things to list them all, but I will mention one. The October 2nd issue of Science contained 11 articles in which the great paleontologist Tim White and his many colleagues described in detail the fossil species Ardipithecus ramidus, unearthed in hundreds of specimens over two decades.

This species, interred by nature for over 4 million years, has now had its eternal rest disturbed, but it is taking revenge by disturbing our complacency. Walking upright on the ground, but with apelike feet for clambering in the trees, it is the clearest example of the transition we have so far, a million years before the justly famous “Lucy” species. The bishop’s wife, if she is listening, has never been more chagrined.

But the news doesn’t end there. Ardipithecus males are very similar to females—around the same size and with small canine teeth. This means they were not competing very fiercely for mating opportunities. In the light of neodarwinian models of behavior that have made many people think differently of late, this creates a new view of our origins.

It rules out, for example, an ancestor just like the chimpanzee, a species where males are brutal to females and, even fatally, to each other. It suggests instead that we arose from a species with less violence and more shared parental care of the young, which is looking more and more like a key to our evolution.

I don’t know how this will ultimately be resolved. Will the answer affect your view of yourself? I have to say it will affect mine. And in this case the “new” biology is more than 4 million years old.

Which brings me to a slight disagreement with Monica. While the self entails a uniquely private viewpoint, the mind it sees is not unique. Not just since Darwin but since Linnaeus, we have known that we share some things in common with all human beings, some with all apes, some with all mammals, and so on.

Part of the new genomics, different enough from genetics to deserve its new name, has been a clear confirmation of these shared heritages. But I used to say we were 99 percent chimpanzee, and I can’t any longer. Why? Because the past decade has revealed that much of what we called junk DNA is not junk at all, but is making RNAs that have crucial regulatory functions.

We have no idea as yet how much our regulatory RNA differs from that of apes, but we already know that their evolution has been exceptionally rapid, especially in the brain, where the complex, poorly understood hierarchy of our genomes controls the course of development.

Still, it is clear that the genome is widely shared among all humans, and that is why there are many universals of culture and mind. Cultural anthropologists like to stress the differences, but my two years among the !Kung Bushmen of Botswana made me think long and hard about the similarities. Modern humans arose in Africa over a hundred thousand years ago and spread throughout the world; we are one species, with different cultures but profoundly similar minds, and similar selves.

But that doesn’t mean there are no important differences, and that’s where personal genomics comes in. Steve has explored his own genes, and we all will have that option increasingly in the future. I learned in medical school and in life that few things separate people as illness does, and specific illnesses create exclusive clubs of shared subjective experience that almost entail new selves for the members.

What happens when you find out that you may be destined to join one of those clubs in the distant future? Well, if the club is one you can easily do something about—say, the Type 2 diabetes club—your self becomes an agent in changing your destiny. When there is little you can do—Alzheimer’s for example—other than doing away with yourself or buying long term care insurance (if you can still get it), does your self now include passivity and victimhood? I don’t know.

Not yet, but some day soon perhaps, personal genomics will tell us something about the things Noga studies—whether we are phlegmatic, say, or choleric, although we’ll use different words. What will this tell us? If your life has told you that you are a timid person, what will genetics add? a greater sense of calm about it? a new passivity in the face of something that might otherwise be changed?

What if you find you have a genetic tendency to exploit others? Will this lead you to want to change, or to justify what you do? The genomic self will raise many new questions.

It will also answer some. In between the selves we share with the species and the selves no one shares, there are intermediate sharings: identical twins, families, ethnic groups, and cultures. Finding ethnic origins in the genes is very important to some people, for example for some African-Americans. When you have had your origins torn away from you by oppressors, you may especially need to explore them. Listening to Henry Louis Gates, Oprah Winfrey, and others talk about what they found and how it affected them, it is impossible not to be moved.

But although Gates and, say, the rapper Diddy probably share ethnic genes, they belong to different cultures, and I suspect this is at least as important in their self-definition.

And this can easily go too far. The other day a brilliant lawyer who should have known better said to me half-jokingly, “What if I find out my wife is not Jewish?” I know them well, and she is Jewish, period, no matter what the genes say. Yet it is clear that such information could somehow change their view of themselves.

We will not be in complete control of how we react to these and other biological revelations. Which brings me to brain imaging.

This, I would argue, is at least as important a biological revolution as genomics, but it requires an even subtler philosophical approach. Let me give you two hot-off-the-press examples.

Steve is a coauthor of a beautiful new study of language and the brain, published in Science on October 16th. It uses a combination of functional magnetic resonance imaging and recording from electrodes in the brain to parse the exact ways in which Broca’s speech area sets up a meaningful utterance.

Without going into detail, I will say that this is an extremely important study that begins to take the mystery out of language generation and, in my view, supports the long-standing claim that the human brain is uniquely, and in a modular way, adapted for language. For myself, it strengthens my sense of separation from the apes, and my shared biological heritage with all humankind.

The other study, equally beautiful, published in Nature one day earlier, provides a remarkable contrast. It is called “An Anatomical Signature for Literacy,” and it proves the profound power of human agency over the brain. It begins:

After decades spent fighting, members of the guerrilla forces have begun re-integrating into the mainstream of Colombian society, introducing a sizeable population of illiterate adults who have no formal education. Upon putting down their weapons and returning to society, some had the opportunity to learn to read for the first time in their early twenties, providing the perfect natural situation for experiments investigating structural brain differences associated with the acquisition of literacy…

The study, done in Bogota and at the Basque Center for Science in Bilbao, showed that learning to read, even in adulthood, specifically increases the anatomical connection between the two halves of the brain, in areas linking vision and language.

The young former guerrillas decided to put down their weapons, learned to read, and changed the anatomy of their brains. It is hard to imagine a better case for the ability of the subjective self to change the objectively visible one. The study is one of many warnings to those who may too readily conclude that if something is seen in the brain, it must be causing what is seen in the mind.

Not so. It is only a correlation, another set of data to be meticulously compared with those of thought and behavior, leaving the task of discerning causality as difficult as ever, sometimes more so. Yet it is very, very important data, and it can certainly change our sense of ourselves—especially if we are among those who think of the mind as something separate from the brain.

Finally, I can’t think about “the new biology and the self” without thinking about the medicines we use today to shape and change ourselves. To cosmetic surgery—rapidly increasing for both sexes—we have added cosmetic endocrinology and most importantly cosmetic pharmacology.

For a child considered “too small” (usually a boy) we have the option of growth hormone; for one “too tall” (usually a girl), hormones that bring on puberty. But in considering the implications for the self, we want to look at adults who choose for themselves: The older man or woman who takes testosterone to restore or enhance sexual drive, or growth hormone to increase strength and energy.

Do they become subjectively younger as they become more sexual or energetic? They certainly seem to feel better about themselves.

Surgery clearly has ambiguous consequences. People who have facelifts may wear turtleneck sweaters because they feel self-conscious about their necks; they live in a personal space between natural aging and the more or less successful pretense of youth. A friend of mine had a nose job in her teens; she certainly adjusted to being seen as beautiful, but she also said she always felt like an impostor.

Is this also the case with psychoactive drugs? Antidepressants like Prozac have lifted the moods and calmed the anxiety of many, and because the side effects of the new-generation drugs are small, most people who take them just feel “normal.” Only the daily ritual of pill taking may bring to mind the thought that they are not quite themselves. But generally they like the new selves very well, thank you.

Stimulants like Adderall and Ritalin, we know, are no longer child’s play; adults by the millions modulate their own attention, and their cognitive performance, more or less at will. Modafanil regulates the sleep-waking cycle, enhancing alertness, and drugs that are used in Alzheimer’s, like Namenda or Aricept, may find uses as cognitive enhancers for “normal” people.

Creative people with bipolar disorders often titrate their own lithium or valproate to try to achieve inspiration without mania. And millions of men, erectilely dysfunctional or not, use Viagra and similar agents to make sex work on call, sometimes exploiting women in the process. We are told the drugs are not aphrodisiacs, but getting a good erection is, so you figure out what they really are.

Does the man who takes daily Cialis have a more normal-feeling sexual self than the one who must take the pill each time he and his partner feel ready? What of the woman who takes the pill off-label? Does her self get a delicious added feeling of wickedness along with the lubrication and clitoral erection?

Stay tuned for the answers, which will not be easy ones. Just over the horizon are countless other choices—cognitive enhancers, true aphrodisiacs, energizers, serenity agents, and more. New technologies of drug production and screening guarantee it.
We can perhaps take comfort in the fact that humans have used herbal mind-altering substances since time immemorial, to enhance everything from visions and trances to meditation and sleep. Traditional cultures have managed to integrate their drugs with their sense of self, and, I suppose, so can we. But we will have an unprecedented array of options at hand.

Some bioethicists insist that we not use them, that we should be satisfied with whatever endowments we have. I don’t agree.

What really counts in all this is agency. If you take our evolutionary past, or the facts of your own genome, as an excuse to be passive, greedy, or violent, that is one kind of consequence for the self; if you insist on saying It wasn’t me, it was my brain, or my genes, then I suppose the new biology trumps the self. But that kind of choice is more a consequence of who you were going into it than who it really made you.

If, on the other hand, you use the information about these things, or the medicines your doctor is willing to give you, to enhance your range of choices, and perhaps strongly go against the grain of what your tendencies may be, that is different.

If you refuse to know these facts, or completely reject drugs, that’s fine too, but you will be living in a world where you have to make those choices, and where many people around you are making different ones; even this fact must change your concept of self.

In the end we must hope that the main result will be an enhanced human agency, both at the individual and the species level. And we can hope against hope to believe in the old saying, The truth shall make you free.