Heritability - biological and social

In the third article of a four-part series Mike Belbin discusses ‘inherent character’. Today this is no longer ascribed as racial, but is put down to a person’s genes

Twins: studied

In 1945, overt racialism in the form of Nazism was defeated. Consequently in the battle of ideas, western states made concessions to humanist and universalist understandings of the human being, while racial/eugenic views became taboo. However, notions of the culturally advanced and backward, created in the industrial era, were used to back up the inequality of nations and regions (Africa, the Middle East). Then, in our new era - the 1980s to 2000s - the obvious rise of the super-wealthy few saw a comeback for genetic ideology. In other words, the self-serving notion that character is rooted in biology: you are your body; your social failure is imprinted.

A gene is a molecule of DNA that determines an inherited trait in an organism. The total genetic material of an organism, or genome, includes both the genes and non-coding sequences and can be made up of one or more chromosomes. A chromosome can have up to 500 million base pairs with thousands of genes.

It was Gregor Mendel (1822-84) who began the serious investigation of how different combinations give each individual organism their characteristics. Mendel realised that the genes from each parent do not blend, but pair. Each gene from each parent has a couple of traits, called alleles, and only one of these is passed on to the offspring to combine with one allele from the other parent. This pairing is by chance, within the reproductive soup. Mendel tested this with pea plants - specifically with the colour traits of ‘green’ and ‘yellow’.

In a gene where the two alleles are different, one is ‘dominant’: that is, it masks the effects of the ‘recessive’ one. With this there remains the possibility that, when someone’s offspring mates with a partner, the recessive gene may combine with a similar allele of the partner and produce an organism where the other trait emerges as a characteristic. In his pea plant tests, Mendel produced many yellow, and yellowing, peas before the process, in a second-generation cross-breeding, came up with peas that were all green.

Traits in humans too are a matter of chance, but it is up to us to deal with the outcome. One way of not dealing with it is to fatalistically assert that everything is delivered by genes and so is unalterable.

In his recent book Not in your genes (2016) Oliver James, the child psychologist, makes a case against this particular trend in biology, which he calls geneticism - the idea that genetic inheritance is not merely physical, but psychological. In fact, the tracing of character back to genes acquired the name psycho-genetics in 1951 - a term used throughout the 50s and 60s until it was renamed behavioural genetics.

Oliver James is not unscientific enough to say that nothing physically inherited has a bearing on psychological development. Rather, he argues, what is ‘passed down’ within the family experience is not just traits of DNA, but patterns of nurture, good or bad. What James challenges is the supposition that there are genetic codes, which transmit a person’s psychological characteristics from parent to child.

Why should researchers wish to find such inbuilt codes? It is not only the celebrated mapping of the Human Genome Project1 that has made such quests fashionable: there is a growing demand for a clear medical label applicable to certain conditions. Finding a definite bodily source - an inborn disease, a particular genetic code - does not, of course, imply that the condition had to be lived with. In fact, it may very well be used to indicate that the condition could be treated by chemical means - 40% of websites that offer biological explanations of mental illness are backed in some way by pharmaceutical companies.

The psychiatric profession itself is divided over genetic explanations for behaviour. James, however, points out that the mapping of gene structure has so far failed to come up with any collection of genes that predispose us to such things as high intelligence or the will to murder. For James, human psychology is not a biological programme, but an acquirement. Despite some continuing mysteries like the range of sexual preference, what mostly matters in character is the habits of the older generation, the child’s position in the family and social expectations as to factors like gender. These count for more than chromosomes or the size of the child’s cranium or skin pigment.

James certainly does not dismiss nature-nurture interaction entirely. One product of such a mix he gives is skill at soccer - his own and his offspring’s. When James was a kid, he was good at playing football. In fact he is sure that his skill, particularly in dribbling the ball, was down to an inherited biological mechanism. There was a pattern of chemicals inside him which, when released, switched certain genes on and off. His son inherited the very same physical propensity, or skill, but grew up better able psychologically to cooperate. James junior was so good he was talent-spotted and subsequently trained with a professional club for two years. James’s point is that physical skill was not enough - training and attitude were just as important.

Nowadays even the faculty of intelligence itself (IQ) is recognised as a quality that is not static - a given - but something that changes. Early on at school, migrant children often do badly, but later catch up and even surpass the locally born, as they become more familiar with the language. There are people writing articles for this very paper who in previous days would have been expected to only wield shovels or type up other people’s work.

This is not a case of denying predisposition - physical particularities such as longer legs for runners, or a brain for chess, but rather proposes that these imprints are not the only or main input in life. Not every long-limbed person becomes a runner, not every swot is interested in chess. Simplifying the world is not necessarily scientific. As Einstein said, “Everything should be made as simple as possible, but no simpler.”

Separated at birth

One of the most cited evidence for genetic determinism is the study of twins. Those who were ‘separated at birth’ are said to have great similarities of personality, despite different home experiences. The most famous of these studies was conducted at the University of Minneapolis, Minnesota by professor Thomas Bouchard in 1979. The media then gave it a large amount of publicity - the story being a particularly easy one, as it says that X causes Y: the cells in your body give you your character.

Oliver James refers to a critical discussion of the ‘Minnesota twins’ study by journalist Lawrence Wright in his Twins (London 1997). One problem in Bouchard’s results that Wright highlighted is that he refused to allow the data to be examined by independent assessors. His work became suspect too when it was learnt that he received funding to the tune of $1.3 million from the Pioneer Fund of New York - a group that had also financed projects advocating racial segregation.

The twins featured in the study were not in fact ‘separated at birth’. Some spent two years with each other, or at least in contact, before the study began, and when they were separated they were placed in largely similar home environments. The twins themselves, even when not identical, were still of comparable physical appearance, which might have elicited similar responses from parents and peers. Later, when it came to interviewing the twins, financial and other incentives were introduced, which might have encouraged the subjects and their carers to exaggerate the required result. Some of the twins also received money from TV and cinema adaptations. One pair, nicknamed the ‘Giggle twins’, told a newspaper that both of them had always wanted to be opera singers though neither had mentioned this ambition before.

Meanwhile the project’s interviewers and researchers showed a strong bias towards finding similarities. The main focus of their testing was IQ rather than characteristics such as a propensity for violence or bias in choosing a sexual partner. The project also sidestepped the criticism that some of the supposedly conclusive evidence could be coincidental. Furthermore Oliver James makes the point that such studies are not reinforced by any corroborative research on the human genome. He is still waiting for the day when the gene for a psychological condition is pinpointed, not just wished for.

Twin studies continue to be a chief pillar of psycho-genetics, along with investigations of children generally - such as the offspring of drug-addicted parents. The Wikipedia page on ‘Behavioural genetics’ comments that “the simple observation that the children of parents that use drugs are more likely to use drugs as adults does not indicate why the children are more likely to use drugs when they grow up”.2

Some studies assert that children born to addicts, even if placed in a new ‘rearing environment’, could have “inherited drug-use-predisposing genes” from their parent, which put them at increased risk as adults. What is surprising and counterintuitive is that these “adoption studies” only “find a small to negligible effect of the [second] family environment on use of tobacco, alcohol and marijuana, but a larger effect if the second family themselves take ‘harder drugs’”.3 In both cases, genetic predisposition only seem to work for one environment.

Other tests may reveal the unreliability of genetic determinism as to gender. In Behave, Robert Sapolsky’s recent book (London 2017), researchers who conducted a global test in mathematics - that was supposed to show a genetic difference between the sexes - could notexplain why the gap between girls and boys was greatest in Turkey, insignificant in Norway and Sweden, and was reversed in Iceland, where the girls did better than the boys.

Manipulation

Siddhartha Mukherjee’s The gene: an intimate history (New York 2016) shows how large the ambitions of genetic research have become: “Soon,” he writes from his base at the Massachusetts Institute of Technology, “we will be ready to write our own instructions. In other words, we will be able to manipulate our own genetic future, snipping genes from embryos or adding new ones.”

There may still be problems in manipulating physical particularities, such as cancers and heart disease, though this might turn out to be a medical advance for us all. But in the pursuit of this there is the danger of the category-mistake that Oliver James identifies. Heart disease, a major killer in the western world, could indeed lead back to a cell, as with cystic fibrosis.

On the other hand, can there be a gene for overeating, which can lead to heart failure? My late younger brother was obese at 14. Did he have a deadly gene or was it because he was compensating for being the only one in our family to attend a strict grammar school?

At one point Mukherjee attempts to sketch out his view of a compromise between the influence of genes and environment - that mixture again. He refers to Caliban - the slave of the magician, Prospero, in Shakespeare’s Tempest. Prospero states that Caliban is “a devil, a born devil, on whose nature nurture can never stick.” (Those who remember the play will know that Caliban is indeed able to learn things, as he reminds his master that “You taught me language; and my profit on’t is, I know how to curse.”) However, in referring to Prospero’s devil insult, Mukherjee sympathises with Caliban and states that the character’s unnurtured nature is “vastly more tragic and more pathetic than anything human”.

Having started to define the human, Mukherjee concludes:

Genes must carry out programmed responses to environment. Otherwise there would be no conserved form. But they must also leave exactly enough room for the vagaries of chance to stick. We call this interaction, fate. We call our responses to it choice. An upright organism with opposable thumbs is thus built from a script, but built to go off-script. We call one such unique variant of one such organism a self.4

OK, but what exactly are “vagaries of chance”? They sound like certain unique occurrences in an individual’s life, like being hit by lightning or being born in the house of a psychopath. This seems to assume that every life-change is accidental, even though one’s early experiences may result in successful ‘social mobility’ or someone as tragic and pathetic as Caliban - who can be pitied, but will probably have to be kept locked up.

But there is another kind of interaction - not the product of accidents peculiar to a family or life experience, but the effects of a particular social system: class position, gender expectation, racial classification and alternative ideas. Not biological luck, but where you live. Genes are not our commanders, giving us orders for the rest of our life, but part of a complex modular system - one small part of a person interacting with the other ingredients in their whole life experience.

In the last part of this series I will discuss a definition of the human beyond the genetic model - one which, while not ignoring biology, rejects genetic determinism.

Notes

1. https://en.wikipedia.org/wiki/Human_Genome_Project.

2. https://en.wikipedia.org/wiki/Behavioural_genetics.

3. Ibid.

4. S Mukherjee The gene: an intimate history New York 2016.