“Free will is an illusion. Our wills are simply not of our own making. Thoughts and intentions emerge from background causes of which we are unaware and over which we exert no conscious control. We do not have the freedom we think we have.” Sam Harris, in his book Free Will

This is not an argument that we can’t make choices, only that we don’t understand or control our hidden motivations for the choices we make, and therefore, we don’t control or understand our choice-making. He also points to the genetic factors that are becoming more understood as the science evolves of the genetic factors that contribute to our motives. To clarify, he adds:

“Consider what it would take to actually have free will. You would need to be aware of all the factors that determine your thoughts and actions, and you would need to have complete control over those factors. But there is a paradox here that vitiates the very notion of freedom—for what would influence the influences? More influences? None of these adventitious mental states are the real you. You are not controlling the storm, and you are not lost in it. You are the storm.”

Last year I read the book Identical Strangers: A Memoir of Twins Separated and Reunited by Elyse Schein and Paula Bernstein. Elyse and Paula were part of a group of Jewish twins (and one set of triplets) who were deliberately separated at birth by their adoption agency and then studied to understand the role of nature vs. nurture. The book is compelling, and interspersed with facts about twins that are surprising and disconcerting.

“Even in cases where there is a great disparity in education and home environment, separated identical twins are shown to be more similar in their IQs than fraternal twins and adoptive siblings of the same age.”

Inherent intelligence can be taken even further, as in this example:

“In the case of separated British identical twin girls, one attended exclusive private schools and the other grew up in a lower-middle-class setting and quit school at sixteen. When the twins were tested at MSTRA as adults, their IQ scores were only a point apart. Robert Plomin, a professor of behavioral genetics at King’s College London, found that the IQ scores of identical twins were nearly as alike as the IQ scores of the same person tested twice.”

In other words, despite the prevalent thinking that we can read to a child and greatly alter their outcomes or send everyone to college and suddenly have a much smarter populace, the likelihood is that genetics are the greatest factor, unseen and unknowable, in how smart individuals are. What else is driven by genetics rather than environment? Potentially a lot. Paula and Elyse found that their political views differed from both their home environments in the same direction:

“Compared to our parents, who tend to be more middle of the road, Elyse and I fall somewhere left of center. One would expect that our political views would be entirely shaped by our environment, but research suggests otherwise.”

That either indicates that one’s political views are more genetically-driven than influence-driven, or it could mean that rebelling against parental views is a genetic trait! We all know that weight and body type are influenced by genetics, but so are factors like what you eat and whether you like to exercise. Genetics hit across several influencing factors:

“Approximately 80 percent of the variation in relative body weight among people is due to genetic differences. Not only can genes influence metabolism, but they can also affect behaviors such as eating and exercise.”

Separated twin studies get even more eerie than this, though, when it comes to twins separated at birth. Consider this story:

“Identical twins Ingrid and Olga, separated at two months of age, first met at age thirty-five and discovered that they had each stopped menstruating around age eighteen. Both sexually active, they each assumed they were pregnant and married their boyfriends. A few months later, they both got their periods.”

What about our moods and a tendency to be happy or depressed? This was something the nefarious twin study that separated Elyse and Paula intended to evaluate by selecting parents with mental illness to track how these potentially biologically inherited mental illnesses manifested in separated twins placed in disparate home environments. Dr. David Lykken shared insight into how one’s genetics affect mood:

“[He] concluded that individuals are born with an innate happiness “set point,” an equilibrium to which their mood returns, despite life circumstances. . . About half of your sense of well-being is determined by your set point, which is from the genetic lottery, and the other half from the sorrows and pleasures of the last hours, days, or weeks. . . . [There is] little difference in well-being among identical twins raised together, compared with those raised apart.”

Just because twins tend to behave the same way doesn’t mean that they understand that it’s inherent. We all create what we think are rational explanations for our behavior:

“Neubauer writes about a set of male twins separated at birth who were both neat and clean to a compulsive degree. One brother attributed this tendency to the fact that his adoptive mother was so fastidious and the other one blamed it on the fact that his adoptive mother was a slob.”

If the following example of twins doesn’t raise an eyebrow, it should:

“The Jim Twins discovered they both drove the same type of Chevrolet, chain-smoked Salem cigarettes, and liked stock car racing, woodworking, and football. They both weighed 180 pounds and they had identical blood pressure. They had each undergone vasectomies and suffered from hemorrhoids, high blood pressure, and migraines. Both had grown up with an adopted brother called Larry and, as children, each Jim had had a dog named Toy. They both married women named Linda and then, after divorcing, married women named Betty. One Jim had a son named James Alan. The other Jim’s son was James Allan.”

If you’ve ever felt like the odd one out in your family, there’s a reason for that:

“Bouchard determined that identical twins reared apart were more alike than fraternal twins reared together, which suggests that growing up together does not necessarily make family members more alike.”

So while your own traits may be in your genetics, bear in mind that you only share about 50% of your DNA with your direct family members but twins share 100%. That’s a big difference. Thomas Bouchard conducted a famous study of identical twins separated at birth, starting in 1979. More information can be found here.

“Bouchard and his team have published about 130 papers detailing their findings, which suggested that adult identical twins perform about the same on most physiological and psychological tests, regardless of whether they were raised together or not. “I wanted to find out how the environment works to shape psychological traits,” Dr. Bouchard said in Kay Cassill’s Twins: Nature’s Amazing Mystery. “But every conceivable trait we’ve looked at turns up some genetic influence.””

“Virtually every theory since Freud had suggested that primarily environment shaped personality. Bouchard found otherwise.”

What do you think?

  • If personality and choice are mostly driven by genetic factors, how much responsibility do individuals bear for their choices?
  • Is free will an illusion?
  • Is it helpful to understand through DNA testing or other means what aspects of our personalities are driven by genetics?
  • Do you have a happiness set-point to which you return despite setbacks and successes? Is it higher or lower than that of other people you know?