Ep 217: Why Your Teen Thinks Differently

Andy: So talk to me a little bit about this, the book's called The Neuroscience of You, How Every Brain Is Different and How to Understand Yours.

Chantel: I always tell people that anyone who has been awake and behaving, and particularly parents, especially if you have more than one child, but even if you're trying to figure out how your child works and how they're different from you, everybody understands intuitively that we don't all work the same. I'm not wired that way. And it was this fact that got me into neuroscience. I started out premed and I had this aha moment when I learned about Phineas Gage the railway worker who had an iron spike blown through his frontal lobe. And I think he probably got many, many people interested in the field of neuroscience because of the way his behavior changed after this accident. And it occurred to me that the brain is this organ that makes the individual themselves. If you change the brain, you change the individual. And yet the vast majority of science, let alone the books on the shelf about how brains work, takes this one size fits all approach. Like brains work like this.

Andy: Yeah, exactly.

Chantel: And that research, the science is based on a group average, which is just a characterization of how brains work when you blur over the individuals. And so I was like, this isn't what I want to know. It's like taking a group of people and saying, the average individual in this room is 5'7. It might not describe any person in the room, let alone saying that this is the perfect way to be. Just like this is the blurred data.

Andy: Yeah, it's normal. We want to be normal.

Chantel: Exactly I wanted to write a book that explained how different brains work within that varied space. I can always tell how long I've been doing research, 25 years, because my daughter was 17 months old when I first scanned a brain.

Andy: Yes.

Chantel: So for the last 25 years I've been trying to figure out the relationship between the mind and the brain at the level of the individual.

Andy: And that was interesting moment in the book too, with the scan of your daughter's brain and realizing that it was kind of backwards compared to all the other babies that you had been scanning at the time.

Chantel: That's so true. Talk about awkward learning moment. I was so young and I was learning how to analyze data and I was sure I did something wrong in the analysis because I'm like, this isn't how brains work.

Andy: They put the mask on backwards is what's...

Chantel: And then I was doing it over and over and I kept getting the same answer. And so I talked to my supervisor and she said, "Is there any chance that your daughter is left handed?" And what's cool is that as soon as I started paying attention, because if you're not a handedness researcher, kids start to display regular preference for hands, usually around the age of two, 20 months and above. And so as soon as I started looking, I was like, oh my gosh, she is lefthanded. But it's so cool that her brain told me she was lefthanded before her body did, her behavior did.

Andy: First part of the book is really talking about how the brain is specializing and breaking down different parts of the brain to do different things, breaking it in half. But then it's also increasingly specializing different modules of clusters of neurons and just have different roles. Can you walk me through that a little bit? And you talk about how there's pros and cons to this. I guess obviously our brains do that because it helped us somehow.

Chantel: Totally. And I think that that's one of the things I really hope people will learn to appreciate. I think we don't talk about differences because there's this societal predisposition to say this is the best way to be, this is the worst way to be. But there are so many interesting spaces in the brain where there are trade offs. There are different brain designs where you have a cost and a benefit and I think specialization is one of those things. Every vertebrate animal has two hemispheres that are largely processing the world independently and then sharing the outputs of these processes rapidly. So you perceive the world as a connected whole, but you've got these kind of two brains working in parallel to solve different kinds of problems.

And one of the interesting ways that people differ, a way that you have access to figuring out without scanning your brain, is how different those two processors, those two hemispheres are. And there are many, many different theories about why we become like this, but handedness is a really good clue as to how lopsided or how different these two hemispheres of your brain are. So left-handed people in general tend to have more balanced or more similar kinds of processing happening in the two hemispheres. My daughter, Jasmine is very, very strange in a lot of ways, which I love her for. But the fact that her brain is still lopsided, it's still very specialized, but actually in the reverse order from a typical right-handed person.

Andy: Well, because also if you're left-handed, you're forced to still do things right-handed because so much things seem to be just set up that way in our culture and stuff like that. It's really hard to go full lefty because you have to exist in the world-

Chantel: You're right. So you're, well you're left in this case, but if you have symmetrical skills in the two hemispheres and in the two hands, most people will lean right handed because of the way the tools and the desks and the environment is set up.

Andy: If everything else was equal, right would probably be easier just because the world is kind of set up that way in a lot of ways.

Chantel: Exactly. And fortunately we don't currently live in a society where we force people to use their right hand, but it is still the case that if you had a 50-50 chance more people would lean right-handed. And I think that that's important because a lot of people who identify as right-handed might have brains that look closer to left-handed people because of this, because they've been pushed this way than somebody who's strongly right-handed, like couldn't open a door with their left hand. And those are the classically lopsided people. So when it comes to specialization, the more different your two hemispheres are from one another, the more systematic the job assignment becomes.

And we think this is in part because when people have very big differences in lopsidedness, it arises from structural differences, it arises from patterns of connectivity in the two brains. So the way I describe this in the book, it's like if you have a team of individuals and one has very strong visual, spatial, graphic design skills and one is a very strong verbalizer is really good with choosing words or a very strong verbal communicator, you're going to assign jobs differently to these people. Your team will function well if you give the person with the specific skills, the jobs that they're better at.

Andy: Hey, you're pretty good at this, maybe you want to handle this one.

Chantel: Yeah, it would be weird to give the verbal person a graphic design job if you had a better person on the team. So that's how the brain works. When you have a part of the brain that has a good computational specialty, it winds up getting jobs that are more similar to one another and then it can become very, very specialized for those jobs. But in the brain, that means that team becomes worse and worse suited or that part, that team member becomes worse and worse suited for other jobs. So I get very good at big picture integrated things or visual spatial skills or verbal skills. That part of the brain then becomes less and less well suited for doing other things. So when you talk about the costs and the benefits, what you really see is that there's a vulnerability that comes with specialization.

So if I have one part of my brain that's excellent at verbal skills, it's fine tuned, it's specialized. And that part becomes overwhelmed because there are more verbal jobs going back to the team member. Let's say one is miserable at verbal skills and one is great at it, but we have a job now that requires only verbal things. And the person who's good at visual facial skills is just picking their nose. But the person who's good at verbal is overwhelmed. Yeah, exactly. So in the brain when it comes to specialization, that means you have fewer and fewer parts that are better and better at specific things. So if you have a hard job or if you get an injury to that part of the brain, there's less redundancy built in. So there are costs and benefits to this idea of having specialized versus multipurpose regions of the brain, hemispheres of the brain, so forth and so on.

It's interesting to note that people differ a lot in this way. And this is something that's totally missing from our stories about how brains work. In part because neuroscience, especially human neuroscience, has largely ignored the 10% of the population that identify as left-handers. For the most part, they're not included in research at all. So we don't know enough about how people like my daughter who didn't grow up in a lab, we don't know enough about how their brains work.

Andy: Something I thought was really interesting because you're talking about the right and left handed and then also how that corresponds to the right and left sides of the brain and that you can start to get ideas about how people's brain works based on whether they're right-handed or left-handed. And you have a quiz in here by thinking of it not in terms of either right or left-handed, but on a continuum. Whereas we're all sort on this continuum of somewhere between fully right to fully left or we're somewhere in the middle and starting to notice the nuances in there. It is really interesting. And how we also process emotions.

Something that I thought was really interesting was just when you were talking about the summarizing these findings on the different sides of the brain, because people talk about right brain versus left brain. But I love what you just summarize it here, which is that one of the key computational differences according to Goldberg and Costa is the left hemisphere takes more of a divide and conquer approach using expert modules to focus on tree level details where the right hemisphere is specialized for looking at the big picture on the forest level.

Chantel: It's so cool because everybody understands that we don't all work the same. And you'll hear people say, I'm not wired that way. Or you'll hear people say, I'm so left brained, right?

Andy: Yeah. Oh totally.

Chantel: It's like one of the only pieces of language we have in popular psychology that talk about neural differences. It's just not quite right. We have this idea that a left brain person is analytical by nature and that this means that they're only using one half or that the left hemisphere is dominant and that a right brain person is a creative thinker. And these ideas are loosely based on some really cool research by Michael Gazzaniga and Roger Sperry, et cetera. Looking at people who had actually had the connection between hemispheres severed. You can then display information to each hemisphere independently and ask them to report, to do something with it.

And so what's fascinating to me is that one of the things Gazzaniga noticed when he was a graduate student is if you talk to a person, most people have speech controlled by the left hemisphere. Again, it's this divide and conquer specialized modules, speaking is really fast. So if you ask a question of a person whose brain is severed down the middle when they're talking to you, they're talking from their left hemisphere. But if you show something to their right hemisphere, they can point with their left hand or draw something with their left hand. So if you show different things to two hemispheres and asks the person what they saw, they're going to tell you what they saw in the left hemisphere. But then if you give them something in a pencil to draw in their left hand, they're going to draw something else. When they draw something else, their left hemisphere can see what their body is behaving, is doing. And then you notice that they started making up stories.

Andy: Oh, I see. I'm drawing this picture.

Chantel: If you saw a sun and a sand timer, like an old timey sand timer. The patient says, I saw a sun but they draw this timer. And then Gazzaniga says, "Why did you draw a timer if you saw the sun?" And the patient says, I was thinking of a sundial. That's where the idea of an analytical left hemisphere came from what Mike Gazzaniga called the interpreter. This tree focused part of the brain that's job is always to make inferences about causality and why you just did what you did. Which is totally mind boggling if you can think of a situation in which consciousness is divided in the brain, one hemisphere is not aware of what's motivating the other hemisphere. So yeah, there's a scientific basis to the left brain, right brain thing, but that's not the real way that people differ neutrally.

And I think for parents of teens, what might be really, really fascinating or for anybody, for myself as well, is that even in our intact brain, a large amount of what controls our behavior are subconscious habits or reward systems, values about which action is going to be most rewarding. They're implicit or subconscious, I call this the horse and the rider in the brain, the two kinds of control systems. And the vast majority of what drives our behavior, we're not actually consciously aware of. It's the horse, they move towards good things and away from bad things. And that kind of control system keeps most behaving animals alive on the planet, perfectly happily. But yet the rider, our conscious storytelling interpreting part of our brain, it tells us a story about why we're doing what we're doing, but it has limited access to the actual workings of the brain.

And then in teens, one of the things that makes teenage years particularly turbulent for some people is that the horse develops faster than the rider. The reward system and the limbic system in the brain is fully up and functioning sometimes a decade before that frontal lobe riding system knows how to steer, so to speak. And so you might find yourself in a situation where you're discussing why did you do what you did or an interpretation of the world with your teenager, and you might feel like they're telling you a lie, but they might just have a completely different understanding of the world based on the way their brain works. They're left to interpret their data, their why with partial information just like you are. And I think this is a kind of very nerdy thing, but my husband is also a neuroscientist. And so we have these discussions all the time that most people might think are silly, but who knows who better? Do I have a better understanding of myself than he does? It might seem totally obvious because I have access to the inner workings of my conscious awareness.

Andy: Oh yeah. You know what's really going on in there.

Chantel: Yeah, I know how I feel when I behave this way, but my interpreter is telling myself a story about why I did what I did.

Andy: Or do you just have access to a made up-

Chantel: A Yeah. So I'm more biased by that conscious awareness. He observes my behavior with no distinction between what's implicitly driven and what I'm aware of. So you might say he has a more unbiased story about why I do what I do. Nonetheless, parents and teens have this dichotomy as well. Parents have the privilege of having made it through the teenage years, having survived them so they have this kind of different historical understanding of the why's. I remember a very salient moment when my daughter was 12 and there was a friend drama happening, and my very relaxed, very considerate child just came into the room and told me they were going to this person's house to have a conversation. Didn't ask me, just, "I'm going." I remember just taking a break and saying like, "Well, how does this usually work?" And we ask. And then I remember her looking at me and saying, "You don't understand. Everything is changing." And I thought, I do understand. I understand on a much more mechanistic level than you do. Everything is changing.

Andy: It is indeed.

Chantel: Oh boy. And this is the beginning.

Andy: That should be just the model of our podcast. Everything is changing.

You mentioned talking about rewards, how some behaviors are rewarding to us and that was something I thought was really fascinating in the book, because you talk about dopamine. And one thing you talk about is when some unexpected reward happens and we get this little boost of dopamine, but the same unexpected reward would affect different people differently. And some people might get a bigger boost of dopamine and say, "Wow, that was awesome." And some people maybe get a smaller percent. And what was interesting to me is linking those ideas up to these concepts with introversion and extroversion, that more extroverted people are the ones who tend to get that bigger hit of dopamine from the unexpected rewards, which then starts to really help you to understand why someone would be more extroverted. Because hey, unexpected rewards feel awesome to me, then I'm more motivated to go out and try to find some and do things I've never done before and meet people I've never met before and try stuff and explore it. Whereas if it's not that big of a reward for me in my brain, then I'm kind of like, well, yeah.

Chantel: Yeah.

Andy: Or I could just chill, read a book and I don't know.

Chantel: Yeah, I thought that was fascinating as well. And cool because some of the work I talk about was actually conducted by one of my friends in graduate school who's a very smart individual, but a lot more introverted than I am. He describes himself as an introvert with bursts of extroversion. But we all are learning about ourselves while we're doing this research. And there are a few things to note about dopamine that are fascinating with respect to the individual differences. The first thing is that your brain does not respond to the world's objective goodness. It responds when things are better or worse than you expect them to be, when the outcomes of your actions are different than what your brain predicted. People might be surviving in war times or hungry or living in objectively terrible situations, but be getting dopamine because they woke up, they're still alive.

In this way your brain is always setting you, your implicit reward systems are always setting you up to need more than expected to feel good. So if you have the opposite, if you have riches of rewards around you, it's really hard to find happiness because you need something to be. In the book I talk about, what would it be like to wake up as Beyonce because she always gives these amazing performances. And how pleased would you have to be with your actions if you were Beyonce? I think if I woke up and did a Beyonce performance, my brain would probably die of dopamine overdose. But if you are Beyonce, that would be such a bummer because you have to be better than normal Beyonce to get-

Andy: Yeah. It was all right. That show was pretty good, I guess.

Chantel: But maybe it wasn't Beychella but it was okay.

Andy: Yeah. But when I sang that song three years ago at the Grammy's, man, I hit that note just so well and I'm never going to hit it that good again.

Chantel: Yeah. Beyonce's brain must have such a struggle. So thinking about the fact that dopamine doesn't respond to the objective goodness, it responds to your predictions. And now when you come to introverts and extroverts and when you think about parenting, what's really important, what I think many people don't understand is that dopamine, not only does it make you feel good, and that motivates. Like you were saying, in an extrovert, I'm going to go out and do things to seek those dopamine rewards. Dopamine makes you feel good and motivates behavior, but in the brain it also motivates learning and rewiring. So when you have dopamine, changes the connections between the context that you're in and the action you took. So the purpose of it, it makes you feel good to drive a behavior, but in your brain, that changes the likelihood that you'll do that thing again in the future.

So an extrovert is like, should I walk out the door? Here I am in my home. The last time I walked out the door, I found an accidental surprise and it was freaking awesome. My brain rewires and so the chances that you walk out your door and whatever 16 steps it took you to find that reward, they all get increased a little bit.

Andy: Yeah.

Chantel: So the reward drives the learning and drives the behavior.

Andy: You quickly learn like, "Oh hey, wow, that was good. I'm going to do that again."

Chantel: Yes, exactly. So we have two systems though, and when things are not as good as expected, when you wake up and you're Beyonce and you sing excellent and not stellar or something like that, her brain would get a dopamine dip. Less good than expected. There are these two pathways that are happening that reduces the connection between the place that you're in and the action that you took. So what's very interesting to me is that individuals with different genetic profiles, some people move through life largely motivated by avoiding those disappointments. Their brains are learning more from the time that things didn't work out as well as you expected. Those are what we call the stick learners.

Creators and Guests

Andy Earle
Host
Andy Earle
Host of the Talking to Teens Podcast and founder of Write It Great
Chantel Prat (she/her)
Guest
Chantel Prat (she/her)
psychologist, neuroscientist, studying individual differences, author of The Neuroscience of You, https://t.co/ivjEGYnUl4 all opinions are my brain's
Ep 217: Why Your Teen Thinks Differently
Broadcast by