What Is the Source of Rational Emotions?
SOME YEARS AGO I RAN INTO AN OLD SCHOOLMATE OF MINE, OFER Lipschitz. “We searched for you months ago to invite you to a school reunion held in my home,” said Ofer apologetically. “Someone mentioned that you were living abroad, so we didn’t really make much of an effort to locate you.” Ofer and I, along with all the attendees at the reunion, were in school together for eight consecutive years, from first grade at age six and onwards. When I told Ofer how disappointed I was at having missed the reunion, he tried to comfort me: “We filmed the entire event. Till the next time we conduct a reunion, you can at least watch the video.” The video Ofer gave me included no less than three hours of footage that contained many shots of every single reunion participant.
Two things especially moved me while I watched the video. The first was the fact that nearly everyone (including me) managed to identify each reunion participant as soon as he or she walked through the door, even before they introduced themselves. We were able to do this despite the fact that the last time we had seen each other was thirty-five years earlier, when we were children. This amazing capacity we have is related to the deep traces that facial features leave in our memories. If I were shown a class photograph of other children from the same time period next to pictures of those same children today as adults, I doubt that I would be able to make even one successful match. The way that facial features are stored in our brains apparently differs from the way other information is stored. We often meet people who seem familiar to us, or whom we are certain we have previously met, but we find ourselves unable to recall any details about them—neither their names nor where and when we met them.
The other thing that impressed me while viewing the reunion video was that the facial features of my friends were not the only aspects of them that were entirely recognizable to me, based on my childhood memories. The present occupations of many of them seemed to be entirely predictable. Ofer and Myron, who were entertaining us with their guitar playing at our get-togethers as far back as the fifth grade, had developed musical careers, deriving their incomes from musical performances and music instruction. Tali, who early on had exhibited much more interest in boys than any other girl in the class and had always been the main source of information on who was romantically attached to whom, is now a sexologist and marriage counselor. Yossi, who had initiated and organized most of our social activities as schoolchildren had grown up to be an entrepreneur, founding and directing start-ups.
Personality traits had also been preserved to a surprising extent from childhood to adulthood. Those who had been introverted as children stood apart and alone at the reunion, looking a bit out of place in the socially intense event taking place around then. Those who had laughed often as children laughed just as often as adults, the loud kids had become loud adults, and the handful who had been prone to antisocial violence as children did not show up at all.
Anyone who experiences such a reunion cannot fail to come away with the strong insight that major elements of personalities are determined in the first ten years of our lives. In fact, in recent years an increasing number of scientific studies are revealing that our personalities are fashioned even earlier than that—not in the first ten years after birth but in the nine months preceding it. The full mapping of the human genome is a huge leap forward for uncovering new insights in what determines personalities. One after another, new discoveries are exposing the tight connection between specific personality traits and genetic profiles.
Richard Ebstein, who specializes in genetic psychiatry at the Singapore National University, has conducted a number of very interesting studies on this subject matter, along with several coauthors. In one of these they focused on the genetic basis of generosity.1 As noted in an earlier chapter of this book, oxytocin is responsible for the mutual empathy felt by mothers and their newborn infants. Another hormone that plays a role in creating the mother-child bond is vasopressin, which is important for several emotional and physiological human functions. The main gene responsible for secreting vasopressin is called AVPR1a, which exists in different lengths. Shorter versions of this gene, which tend to create smaller amounts of vasopressin, are more common among individuals suffering from autism spectrum disorder.
Ebstein and his colleagues studied hundreds of healthy subjects and categorized them according to the length of this gene that each one carried. They then had these subjects play the giving game, as described in Chapter 9 (in the giving game, each player receives a sum of money and can donate as much as he wishes from that sum to the other player). Subjects carrying shorter versions of the gene gave much less to others in this game than those with longer versions. This was a clear identification of a (statistically observable) personality trait with the variations of a single gene, in this case AVPR1a.
Other research studies based on comparisons of the behaviors of identical twins have uncovered the genetic sources of several other personality traits. If a certain personality trait is exhibited with high correlation between identical twins (who share the same genetic profile) and low correlation between fraternal twins, that serves as an indication that the genetic component of that trait is more significant than the social component.
Richard Ebstein and his colleagues also conducted a wide-ranging survey of research studies of personality traits and used that to estimate the genetic components of each.2 Figure 2 presents a summary of their results, with two different types of genetic components presented separately: purely genetic components that are independent of social influences are labeled DZ, and more general genetic components—which take into account possible social influences but only those that influence individuals with particular genetic profiles—are labeled MZ.
Figure 2 shows that there is a significant genetic component to a wide range of behavioral traits. In some cases this component is dominant. Most of the research studies on which the table is based are quite recent. The data in those studies, along with additional indications that genetics play a major role in determining personality traits, are reviving the age-old debate on nature versus nurture, which in the past has too often conflated moral considerations with scientific claims.
There is some cause for concern given the potential implications of the research studies mentioned in this chapter. It is now possible to conduct a complete mapping of the genetic code of an individual at a lower cost than ever before. A sample of saliva and $200 are sufficient to identify our genetic tendencies. The more we understand about the genetic component in determining personality traits, the more the private market will be incentivized to make use of the information stored in our DNA. Job applicants may one day be asked to provide saliva samples along with their resumes. Home renters could similarly ask potential tenants for their saliva samples, and insurance companies could use genetic profiles to calculate insurance premiums. This may eventually extend to all our economic and contractual interactions, creating a self-reinforcing cycle: those with “attractive” DNA profiles getting the best jobs, and those with “ugly” profiles being forced to work in more unappealing occupations, or suffering unemployment. Within the span of a few years this sort of discrimination could in itself strengthen the impression that a person’s DNA profile categorically determines his or her chances of success in life. Those stigmatized with “ugly” DNA profiles would have no incentive to seek higher education, learn a profession, or even work hard. Social mobility would slow to a trickle, as a new genetic aristocracy emerges.
Despite these clear dangers, we should not use our fears as an excuse to block future scientific research. Ignorance should never serve as a form of inoculation against potential social dangers. It is already becoming nearly impossible to obtain grants to study the relationship between genetics and cognitive ability or IQ from the major national scientific funds in the United States, the National Science Foundation and the National Institutes of Health. There is no formal decree forbidding such research, but political correctness seeps into deliberations on research funding early on in the process, dooming most such grant requests. Concerns about the potential use of such research efforts to justify discrimination are understandable, but self-imposed ignorance is no solution either.