You mentioned genes sometimes and usually in the literature in neuroscience and psychology we read about some genes that have some effects on our behavior. Sometimes they couldn’t cause diseases, sometimes they can. We can inherit some traits, but how easily we can relate some mind or psychological features or traits to genes?

I would like to acknowledge that it is no easy task. It is extremely hard, but we believe if you do it in a smart way, there’s no reason to be afraid of genes in trying to understand the complexity of the human mind. I think sometimes people oversimplify when they talk about genes, and they may have some sort of agenda, you know, to say, “Well, it’s in the genes, and you can’t help someone because it’s all in the genes,” or “Nothing’s in the genes; it’s all in the environment.” Those are very simplistic dichotomies, and for most things, it’s a blend between the two. So, my approach is to start with some things that we know are genetically related, and then once we can start there, we can build outward.

I’ll just give you one example. There is a genetic disorder called phenylketonuria or PKU. PKU is a form of developmental delay where there’s cognitive deficits in memory and language, and we know that there is a genetic component, and we’ve identified the sequence. I won’t get into the details of that identified gene sequence, but if you have this gene sequence, there’s a high likelihood that you will develop PKU. However, if you intervene early in life, like if you change the diet of a pregnant mother, if the mother of someone who’s at risk of PKU eats less protein — they have to limit certain proteins — it does not trigger the disorder, and these individuals end up developing in more neurotypical fashions. I think that’s interesting for two reasons. One is it shows that something that seems like the mind, like memory and language, these pretty high-level things, does have a genetic component. It’s not totally reducible to genes, but it does clearly show these complex things like language and memory are related to genes. But the second reason I really like that is that it shows that the environment is a crucial mechanism for either turning on or off these genes. And I think that’s the model that if we’re going to talk about high-level cognition, things like language for sure, we’re going to have to talk about the interplay between some genetic predispositions and then environmental input. So, that’s the first thing. It is possible to connect genes to high-level things like language and memory, but not reduce them just to the gene, which I think both of those are important.

Regarding language specifically, one of the mistakes that we think researchers traditionally have done historically when studying language is to look for genes that are specifically designed for language, so the “language gene.” And most certainly nowadays, most molecular geneticists would say that’s not the right way to think about genes and language. Instead, the way to think about genes and language is to think about all the cognitive sub-processes that allow us to come into being. So, language is not a thing unto itself; it’s really a bunch of smaller processes that need to work together in order for language to operate. And if we can look for genes for those smaller components, now we might be able to start mapping complex things like language down to genes. And so, I think the key insight, and you’ll see this in the next 10 or 15 years with these breakthroughs for very complex behaviors like language, is they’re going to break language into smaller sub-processes and then show the links. So, one link, for example, is there is a genetic link to certain forms of speaking, making motor movements of your mouth, that’s a basic skill. It’s not easy, but it’s a basic skill that if you disrupt, you’re going to have language problems. And we do think that genes tend to map onto basic motor abilities to produce speech sounds. So, the idea is if we can find more and more genes mapping onto the subprocesses, we’ll start to be able to piece together all the different genetic mechanisms for the language, capital “L” Language. So, I think it’s possible, and I just think you’re right, it is challenging. And I would say anytime you see a simplistic explanation, you should probably think that someone’s trying to sell you something that’s not true.

Part of this question was actually about evolutionary psychology, which is mainly based or it should be based on genetics and inheritance of traits, so it would start being an obstacle and a challenge for evolutionary psychology as well?

I think evolutionary psychology that takes a sophisticated view of how genes map onto traits isn’t challenging. I mean, technically it’s very challenging, but conceptually it’s not like a fundamental challenge for evolutionary psychology. My understanding of evolutionary psychology is that it’s a field that wants to try to explain human behavior in terms of its adaptive function, that historically it’s adaptive function, and if you’re going to do that, then you’re going to have to consider genes because we know that that’s one of the methods of inheritance.

So, I don’t see it as necessarily a threat to evolutionary psychology. I do see it as a threat to oversimplified evolutionary psychology. And so, sometimes evolutionary psychology makes the rounds in the news because there are really bold claims like, you know, there’s a gene for aggression. Aggression is a complicated behavior, and it’s likely there are genes for components of aggression, that’s true, or a gene for love, or a gene for language, which is my specialty. Those things are so complex that you’re not going to find a single gene, let alone even like a cluster of genes that are going to map onto anything quite that complex. So, it is a threat for simplistic models of evolutionary psychology.

But there’s enough smart researchers in the field now who are starting to talk to actual molecular geneticists. Evolutionary psychology that does not talk to molecular geneticists, you know, that’s a problem. I think they have to talk to one another if the field is going to grow.

I liked how you simplified the role of FOXP2 in other species in the book can you explain that to our audience?

Right, exactly. The idea there is that evolutionary psychology sometimes misses is that there are a lot of genetic mechanisms that are not unique to humans, that map onto complex things in humans that other species have, even if they don’t have those complex things. Clearly, humans are the only ones that have human language, and you know, capital “L”, Language and its full glory in complexity, yet there are other species that had the FOXP2 gene. The mice have it, dogs have it. It’s quite what’s called an evolutionarily conserved gene. And for a lot of issues, and we think, whenever you see that, it’s likely it’s being used for more fundamental processes that get co-opted by organisms to serve, you know, other functions. And I think, I mean, humans. So, you’ve read the book, and so you know, I don’t think that language, we have a language gene. It’s because we don’t need a language gene. We just need genes for all the things that help you build language over development. That’s what, you know, humans need. That, and it turns out that we have a lot of the genes and genetic mechanisms for language are shared by other species, which is quite fascinating, and it makes you realize you have to think more. It’s a more complex story than just saying language is genetic when we share a lot of the same, you know, machinery with other species.

This post is part of multiple topics about “Language and the Mind”, a podcast that has been published in Real Sciences with Spencer Kelly the co-director of Colgate’s Center for Language and Brain in Colgate University.

Link to Language and the mind: https://www.amazon.co.uk/Language-and-the-Mind/dp/B085SZ9PSZ