What Birth Defects Teach Us About Being Human

Nicki Hornbaker, age 19, was born with a genetic defect called Williams Syndrome. About 25 of the 30,000 gene pairs in Nicki's DNA are not connected. A mere 5 or 6 of those missing connections have led to the prototypical Williams features exhibited by Nicki. Although Williams people have trouble interpreting space and numbers and therefore have difficulty being self sufficient, their primary distinguishing feature is a talky openness and social affability.

They have, "an exuberant gregariousness and near-normal language skills. Williams people talk a lot, and they talk with pretty much anyone. They appear to truly lack social fear. Indeed, functional brain scans have shown that the brain’s main fear processor, the amygdala, which in most of us shows heightened activity when we see angry or worried faces, shows no reaction when a person with Williams views such faces. It’s as if they see all faces as friendly."

In a fascinating article in the Sunday NY Times Magazine, David Dobbs uses the characteristics of Williams to draw a lesson about our social nature as human beings. There is also an interesting video of an interview with Nicki that demonstrates her affability and her limitations.

Occasionally it is important to draw back from the minutiae of our daily lives and our obsessions with politics and other issues and contemplate who we are as creatures of the evolutionary chain. (If you are looking for a discussion of the alleged debate about so-called creationism vs. Darwinism you will have to look elsewhere for now. At this blog there is no such debate. Darwin won. The really interesting question for me is how this process works at the genetic level and how its expressions play out in our lives.)

If people with Williams have a serious interruption in their ability to perceive danger from other people due entirely to a genetic defect, then the need for people to both count on and fear other people, a delicate balance, must be central to humanness. It has apparently been hard wired into our brains. As Julie R. Korenberg of UCLA puts it:

“We’ve long figured that major behavioral traits rose in indirect fashion from a wide array of genes,” Korenberg says. “But here we have this really tiny genetic deletion — of the 20-some-odd genes missing, probably just 3 to 6 create the cognitive and social effects — that reliably creates a distinctive behavioral profile. Williams isn’t just a fascinating mix of traits. It is the most compelling model available for studying the genetic bases of human behavior.”

Another scientist notes:

“It’s not just ‘genes make brain make behavior.’ You have environment and experience too.” By environment, Reiss means less the atmosphere of a home or a school than the endless string of challenges and opportunities that life presents any person starting at birth. In Williams, he says, these are faced by someone who struggles to understand space and abstraction but readily finds reward listening to speech and looking at faces. As the infant and toddler seeks and prolongs the more rewarding experiences, already-strong neural circuits get stronger while those in weaker areas may atrophy. Patterns of learning and behavior follow accordingly.

Here is the key transition in this article from the discussion of a particular syndrome to the larger issues of human nature:

As an experiment of nature, Williams syndrome makes clear that while we are innately driven to connect with others, this affiliative drive alone will not win this connection. People with Williams rarely win full acceptance into groups other than their own. To bond with others we must show not just charm but sophisticated cognitive skills. But why? For vital relationships like those with spouses or business partners, the answer seems obvious: people want to know you can contribute. But why should casual friendships and group membership depend on smarts?

One possible answer a comes from the rich literature of nonhuman primate studies. For 40 years or so, primatologists like Jane Goodall, Frans de Waal and Robert Sapolsky have been studying social behavior in chimps, gorillas, macaques, bonobos and baboons. Over the past decade that work has led to a unifying theory that explains not only a huge range of behavior but also why our brains are so big and what their most essential work is. The theory, called the Machiavellian-intelligence or social-brain theory, holds that we rise from a lineage in which both individual and group success hinge on balancing the need to work with others with the need to hold our own — or better — amid the nested groups and subgroups we are part of.

Competition for food, i.e. for survival, led to the necessity for larger and larger groups. Families merged into tribes.

But the bigger groups imposed a new brain load: the members had to be smart enough to balance their individual needs with those of the pack. This meant cooperating and exercising some individual restraint. It also required understanding the behavior of other group members striving not only for safety and food but also access to mates. And it called for comprehending and managing one’s place in an ever-shifting array of alliances that members formed in order not to be isolated within the bigger group.

This greater need for brain power has led to the evolution of greater brain capacity:

This isn’t idle speculation; Robin Dunbar, an evolutionary psychologist and social-brain theorist, and others have documented correlations between brain size and social-group size in many primate species. The bigger an animal’s typical group size (20 or so for macaques, for instance, 50 or so for chimps), the larger the percentage of brain devoted to neocortex, the thin but critical outer layer that accounts for most of a primate’s cognitive abilities. In most mammals the neocortex accounts for 30 percent to 40 percent of brain volume. In the highly social primates it occupies about 50 percent to 65 percent. In humans, it’s 80 percent.

Dunbar further states:

"... no such strong correlation exists between neocortex size and tasks like hunting, navigating or creating shelter. Understanding one another, it seems, is our greatest cognitive challenge. And the only way humans could handle groups of more than 50, Dunbar suggests, was to learn how to talk.

“The conventional view,” Dunbar notes in his book “Grooming, Gossip and the Evolution of Language,” “is that language evolved to enable males to do things like coordinate hunts more effectively. . . . I am suggesting that language evolved to allow us to gossip.”

We all experience the truth of this human trait in our daily lives. At work, in families and in our social networks we are constantly trading information to garner the lay of the land.

For we are all gossiped about, constantly evaluated by two criteria: Whether we can contribute, and whether we can be trusted. This reflects what Ralph Adolphs, a social neuroscientist at the California Institute of Technology, calls the “complex and dynamic interplay between two opposing factors: on the one hand, groups can provide better security from predators, better mate choice and more reliable food; on the other hand, mates and food are available also to competitors from within the group.” You’re part of a team, but you’re competing with team members. Your teammates hope you’ll contribute skills and intergroup competitive spirit — without, however, offering too much competition within the group, or at least not cheating when you do. So, even if they like you, they constantly assess your trustworthiness. They know you can’t afford not to compete, and they worry you might do it sneakily.

As Dobbs concludes:

To inquire into human behavior’s genetic underpinnings is to ask what most essentially defines us. One of the most vexing questions raised by both Williams research and the social-brain thesis is whether our social behavior is ultimately driven more by the urge to connect or the urge to manipulate the connection.

The traditional inclination, of course, is to distinguish essential human behavior by our “higher” skills and cognitive powers. We dominate the planet because we can think abstractly, accumulate and relay knowledge and manipulate the environment and one another. By this light our social behavior rises more from big brains than from big hearts.

The disassociation of so many elements in Williams — the cognitive from the connective, social fear from nonsocial fear, the tension between the drive to affiliate and the drive to manipulate — highlights how vital these elements are and, in most of us, how delicately, critically entwined. Yet these splits in Williams also clarify which, of caring and comprehension, offers the more vital contribution. For if Williams confers disadvantage by granting more care than comprehension, reversing this imbalance creates a far more problematic phenotype.

As Robert Sapolsky of the Stanford School of Medicine puts it: “Williams have great interest but little competence. But what about a person who has competence but no warmth, desire or empathy? That’s a sociopath. Sociopaths have great theory of mind. But they couldn’t care less.”

Fascinating stuff.