This video is part of a series on genius, in proud collaboration with 92Y’s 7 Days of Genius Festival.

In the late 1990s, scientists thought they were close to locating specific genes that controlled for human intelligence in all its manifestations: musical genius, analytical acumen, physical prowess, etc. But the truth turns out to be more complicated, says Harvard psychologist and linguist Steven Pinker. There are many genes — perhaps thousands — that affect human intelligence, and while manipulating them may have predictable benefits, the adverse consequences remain unpredictable. Thus experimenting with our so-called intelligence genes will likely be met with high levels of skepticism in caution. It’s proof, says Pinker, that technological advancement doesn’t always march to the drum beat of inexorable forward progress.

Steven Pinker:  I think it's unwise to make a confident prophecy in what technology will or won't eventually be able to do. I think that cuts both ways. That is it's people have looked foolish by saying that something will never happen, but they've also looked foolish by saying that something is inevitable. So there are things that we can accomplish technologically that we as a society have chosen not to, such as passenger supersonic air transport. I think if you were to say to someone in 1957 the speed of commercial jets now is going to be the same as the speed of the commercial jets in 2016, 60 years from now, they would say you're nuts. Technology goes up, up, up, up, but sometimes it doesn't. Because people don't like sonic booms and jet fuel got too expensive. Likewise, if you would've said in 1972 no one is going to set foot on the moon for another 44 years and counting, again. They would say technology always lifts us higher and higher, but sometimes it doesn't. The Cold War ended. People lost interest. There are all kinds of social and economic factors that in combination make the future of technology inherently unpredictable. And I think in engineering human intelligence, to say nothing of human genius, no one knows but I would put my money with no. For one thing, there are moral and legal taboos. People think that introducing traits into offspring is a form of eugenics and is on a slippery slide to Nazism. I happen to think that that is a bogus ethical argument, but it is by far the majority that's a cool argument and in many countries genetic enhancement is or will be illegal. And it's going to take a huge force to overcome that. Just as cloning is illegal in virtually every country, when Dolly the sheep was cloned in 1997 there were confident predictions that there's nothing you can do to stop human cloning. It was just around the corner and here we are almost 20 years later and it has not happened.

Also, the task of engineering high intelligence is turning out to be a lot harder than one might have thought. In the late '90s it was thought well sooner or later we'll find some high IQ genes; they'll give you three or four points. You'd put in a handful of them and you get a much smarter baby. There was going to be the gene for musical talent and the gene for athletic coordination. We have every reason to believe that those traits are substantially inheritable. We've known that for decades just because of twin and adoption studies. On the other hand, we also know that the genes responsible are going to, each one of them is going to have an incy wincy effect and there are dozens, hundreds, maybe thousands of them. So making your child smart is not a question of putting in one high IQ gene, it may be a question of putting in a hundred genes or a thousand genes. Every time you monkey with the genome you are taking a chance that something will go wrong. Also, those genes, the ones that we have identified, and we've made enormous progress in just a few years ago there was not a single gene you could point to that had a positive effect on intelligence, now we can point to a few of them. They have incy wincy effects, a third of an IQ point. But on the other hand we identify them with their correlations with intelligence. We have no idea what they do. I mean if you find that any of those genes is actually expressed in the brain then you've had a really good day as a scientist. But to know what the totality of their effects are, positive and negative, is something that we're not going to know for a long time, if ever when you're talking about hundreds or thousands of genes. How do we know that one of those genes that raises your IQ by a third of a point doesn't also increase your chance of epilepsy or schizophrenia or brain cancer. Now, you're going to go to a review board and ask for permission to monkey with a human embryo and they're going to say so we know what the benefits are of implementing this gene, what are the costs? And the answer is we don't know. You think that they're going to have - that that's going to meet approval? Or do you think for that matter that parents are going to be willing to take such chances with the biological integrity of their children? That in exchange for an increase of an IQ points or two they're going to take some unknown risk of making the child schizophrenic or bipolar or some other disease that we may not know of who's probabilities we don't know? Not so clear that they will.

Now, there is the argument parents will do anything to enhance the flourishing of their children. Look at the way parents buy test prep courses and struggle to get them into the Ivy's and so on. I think that's true probably of the social circle of the people who make those predictions where IQ has outsize importance. But even then there are – people do strongly distinguish biological interventions from environmental ones, at least psychologically. That's why we still don't have any sport where athletes can dope all they want. You might say what difference does it make whether you increase your red blood cell count by training at a high altitude or by taking a drug? Well, biologically there may not be that much of a difference, psychologically there's all the difference in the world. We just don't think that it is the same thing when you can cheat and achieve an advantage through sheer biological interventions. I wouldn't say that for sure that's going to stand in the way of parents enhancing their children genetically, but on the other hand I think it's unwise to say that it will have no effect, that we know that those psychological barriers will be overcome.