Some scientists claim that new discoveries have proved free will is an illusion. Nonsense, says Julian Baggini. James Springer and James Lewis were separated as one-month-olds, adopted by different families and reunited at age They shared interests in mechanical drawing and carpentry; their favourite school subject had been maths, their least favourite, spelling. They smoked and drank the same amount and got headaches at the same time of day.
A great deal of who they would turn out to be appears to have been written in their genes. Researchers have even suggested that when it comes to issues such as religion and politics, our choices are much more determined by our genes than we think.
Many find this disturbing. The idea that unconscious biological forces drive our beliefs and actions would seem to pose a real threat to our free will. We like to think that we make choices on the basis of our own conscious deliberations. To address these concerns, we first need to look a bit more closely at what the experiences of identical twins really show. From the start of his research in the early s, it became evident to Spector that identical twins were always more similar than brothers or sisters or non-identical twins.
It is perhaps understandable that Spector got caught up in gene mania. The launch in of the Human Genome Project , which aimed to map the complete sequence of human DNA, came at the beginning of a decade that would mark the high point of optimism about how much our genes could tell us.
Yet these diseases are at the root of many current societal problems. By that time, genes were no longer simply the key to understanding health: they had become the skeleton key for unlocking almost all the mysteries of human existence. For virtually every aspect of life — criminality, fidelity, political persuasion, religious belief — someone would claim to find a gene for it.
The judge turned down the appeal, saying that the law was not ready to accept such evidence. In recent years, however, faith in the explanatory power of genes has waned. Almost all inherited features or traits are the products of complex interactions of numerous genes.
However, the fact that there is no one genetic trigger has not by itself undermined the claim that many of our deepest character traits, dispositions and even opinions are genetically determined. What might reduce our alarm, however, is an understanding of what genetic studies really show. The key concept here is of heritability. Such figures sound very high.
But they do not mean what they appear to mean to the statistically untrained eye. Crucially, this will be different according to the environment of that population. Because people selected to go there tend to come from middle-class families who have offered their children excellent educational opportunities.
Having all been given very similar upbringings, almost all the remaining variation is down to genes. Statistical illiteracy is not the only reason why the importance of environmental factors is so often drowned out.
We tend to be mesmerised by the similarities between identical twins and notice the differences much less. If you can stop yourself staring at the similarities between twins, literally and metaphorically, and listen properly to their stories, you can see how their differences are at least as telling as their similarities.
Far from proving that our genes determine our lives, these stories show just the opposite. When Ann and Judy from Powys , mid-Wales were born in the s, they were the last thing their working-class family with five children needed. So, identical or not, Ann and Judy were packed off to live with different aunts. After three months, Judy returned to her biological mother, as her aunt could not manage raising another child. But for the childless year-old couple who took on Ann without ever formally adopting her , the late opportunity for parenthood was a blessing and she stayed.
Their experience is a valuable corrective for anyone who has been impressed by tales of how identical twins show that we are basically nothing but the products of our genes. Although the girls grew up in the same town, they ended up living in different areas and went to different schools. The two households in which Ann and Judy grew up were very different. The family lived in a basic two-up, two-down house with a toilet at the bottom of the garden.
Ann was brought up in a newly built, semi-detached house, with a toilet indoors. Although, aged 15, Judy was offered a place at a grammar school, when she got there she found herself suddenly studying algebra and geometry in a class where everyone else had already being doing it for three years. Unsurprisingly she struggled. After four months, Judy quit and went to work in a furniture shop. Ann, meanwhile, breezed through school, although she, too, left early because her now year-old father was retiring.
At 16, Ann began her white-collar job in the local council offices, not long after Judy had started working on the shop floor. Less than six months into her job, Ann got pregnant and quit.
Two months later, Judy also got pregnant and quit the nursing course she was enrolled in. Not only that, but both fathers, soon husbands, turned out to be very violent.
However, the differences in what happened next are instructive. I had three children by the time I was The two only really started a proper sibling relationship after Ann read about the Minnesota University research in the paper and wrote to the university about her and her sister. Another major area of inquiry is how genes shape our social relationships.
My colleague Ben Domingue at Stanford, along with sociologists Dalton Conley and Jason Boardman and economist Jason Fletcher, has been working on the question of whether friends and spouses tend to be more similar genetically to one another, and why that might be the case.
And there are more social scientists joining the field every day. You said that the genes you looked at had already been linked to educational attainment, which is, of course, linked to IQ and socioeconomic status.
Do we really need scientific research to tell us that smart, wealthy people get more schooling and therefore achieve more as adults? I think one important contribution of our work is to document that the genetics originally discovered in studies of educational attainment are not about education specifically.
Instead, they relate to a range of personal characteristics—including IQ but also noncognitive skills, like self-control and being able to get along well with others. These traits enabled kids with high polygenic scores to succeed not just in school but well beyond. In fact, differences in education explained only about half the effect on long-term life success we found. Also, even though kids born into better-off families did tend to have slightly higher polygenic scores, higher scores predicted success no matter what kind of conditions a child grew up in.
This is still giving me pause. As I said, given the weak power of our predictive models, Gattaca is not possible today.
But I do think the time for conversation is now. I agree that the idea of using genetics as a sorting mechanism is scary. We rely on all kinds of rubrics to pick winners and losers before people have a chance to actually prove themselves. For example, genes are why one child has blonde hair like their mother, while their sibling has brown hair like their father. Genes also determine why some illnesses run in families and whether babies will be male or female. Genes are sections of DNA deoxyribonucleic acid that are found inside every human cell.
DNA is made of four chemicals that form pairs in different combinations. The combinations create codes for different genes. Each person has about 20, genes. The genes code for different traits, such as eye color, body type, or male or female sex. Inside each cell, DNA is tightly wrapped together in structures called chromosomes. Every normal cell has 23 pairs of chromosomes for a total of 46 :.
To form a fetus, an egg from the mother and sperm from the father come together. The egg and sperm each have one half of a set of chromosomes.
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