TOEFL: Two professors offer contrasting opinions on recent research concerning how genetics affects a person's intelligence.
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It's hard to imagine an idea more uncomfortable than the notion that some people's DNA means they were born to be smarter than others. It's a discomfort exploited in the Hollywood science fiction thriller Gattaca. It paints a picture of a future in which your place in society is determined by the supposed advantages written into your DNA. It's a disturbing notion unfair, even undemocratic. It violates our notions of equality. And yet if you ask almost any behavioral scientist this is what you're likely to hear.
The heritability of intelligence has been studied for almost 100 years, and by now it's one of the most well documented findings in the behavioral sciences that individual differences in intelligence, say learning ability or general cognitive ability as it's called. Those individual differences are very substantially, at least 50 percent, are due to DNA differences between us. That is genetic differences, inherited DNA differences.
That's Professor Robert Plohman. He's a behavioral geneticist at the Institute of Psychiatry at King's College London. Two weeks ago, he and his colleagues released a study identifying 52 genes linked to human intelligence. Genes where small differences in the DNA code made some people smarter than others. Today we're going to spend some time delving deep into what this means scientifically of course, but also from a social and ethical perspective because this is an area where these issues couldn't be more important. That's because whenever we talk about the genetics of intelligence, we bring in the ghosts of the past and the fears for the future. Like eugenics, using genetic technologies to make quote unquote improved humans. Or questions of genetic discrimination, like using people's supposed genetic disadvantages to support racist or antipoverty political agendas. So to start, let's return to Professor Plohman.
Basically, intelligence is learning ability. And any teacher knows that given a class of 30 students, some of them just pick stuff up very quickly, and others have to struggle to pick things up. And that could be skills like reading and math, or it could be more general comprehension. Children just differ a lot. And teachers know it isn't just how well they teach. By finding genes, it'll make the genetics more real. I mean as I say we've known that intelligence is heritable for decades. The things we worry about in school, like class size, it accounts for less than 1 percent of the variance. Gender differences, differences between boys and girls in math and verbal, less than 1 percent of the variance. So we get all bent out of shape about those things, and we ignore something that accounts for more than everything else put together. There's still a lot to play for in terms of getting people to understand first to recognize how different children are and the extent to which genetic differences account for those differences. And then secondly to respect those differences to a greater extent, not to assume that a child who has difficulty at school. You first blame the schools then you blame the teachers and you blame the parents and failing all that, you blame the child for not being motivated not having enough grit or whatever it is. But we need to recognize that children really do differ genetically. And that doesn't mean we give up on children. We just recognize that it's going to take a lot more effort to get some kids up to minimal levels of literacy and numeracy, whereas other children, you can't stop them from learning to read or doing math.
For a somewhat contrasting perspective, I’m now joined by Dr. James Tavery. Dr. Tavery works in applied ethics and the philosophy of science at the University of Utah. He's written on the ethical implications of studying genes for intelligence. Dr. Tavery, welcome to Quirks & Quarks.
Thanks. Happy to be with you.
Now you've studied how the controversies in the study of intelligence have evolved over the years, so can you give me a brief summary of that and take me up to where we are right now?
The father of the nature nurture debate and really the science of studying nature and nurture was Charles Darwin's younger cousin, Francis Galton. Interestingly, Galton was also the father of eugenics, and when Galton created that term it just meant good birth. But eugenics has a very seedy history in the US and Canada, overseas. And of course you know it reaches its absolutely grisly apex with the Holocaust in Nazi Germany. And so Galton wanted to develop a science of nature and nurture, and he wanted to do that because he wanted to change the world. That's a hundred or more years ago. What you see is throughout that history throughout the 20th century and into the present, lots of people trying to figure out, for whatever trait you're interested in intelligent schizophrenia criminality, what's genetic what's environmental. And that's they're interested in that question because they want to use the answer to intervene. Right? They want to see more intelligence and they want to see less criminality. But the very act of trying to you know carve up the world and decide who's better and who's best and to assess that based on what's in our bodies what's in our genome can lead to really really bad things.
Dr. Plohman said that this might help us identify those who need help or those who might be at a disadvantage.
And that strikes me as extremely optimistic. With the 52 genes that we're talking about, everybody is going to have you know sort of some set of what we might think of as better and worse variants in there. And the reality is you know what they did was they found genes that were associated with IQ. But none of the cases do we know precisely how they create that trait that we're interested in. The thought that we could sort of you know genotype kids and say, “Oh you've got more than 30 of the bad ones. Maybe we should think about putting you in a special program.” No way. If you want to help kids, get the lead out of their water. If you want to help kids, get more books in their home. I mean there's so many very straightforward environmental interventions that we know are going to have a positive impact on intelligence.
Does this work reduce or increase the ethical concerns around research into the genetics of intelligence?
Well I wouldn't say a single study reduces or increases it. But I do think it's certainly a study like this lends itself to abuses. So let me give you an example. Many of these same authors were on a paper that came out in 2014 that also looked for areas of the human genome that were associated with cognitive ability. And they found three at that time. Almost immediately afterwards the next year, other researchers came along to look for whether or not those three genes had different distributions in different racial groups because what they were interested in is whether or not minority groups are sort of genetically predisposed to being less intelligent than white people. It's offensive and it contributes to a kind of oppressive narrative that people who are less well-off are less well-off because of something in their genomes. I can guarantee you, within the next five years, the 52 genes that have been identified in this study, somebody is going to come along and try to see if those 52 genes are distributed differently in different racial groups. And so you can't blame the study authors for that, but there is a sense in which the research that they're doing opens the door. These people are lurking in the shadows waiting for these studies to be done so that they can pursue their more racialist interests.
Dr. Tavery thank you very much for your time.
It was my pleasure. Thanks for having me.