Why our brains struggle to keep up with a rapidly changing world

Hello and welcome to Incident Genius, a bite-sized masterclass in podcast form. Every Monday and Friday you'll hear world-leading scientists and experts talking about the most fascinating ideas in science and technology today. I'm Jason Dutger, commissioning editor at BBC Science Focus. The human brain is undoubtedly one of the true marvels of nature, but many of the new mechanisms that evolved to keep our ancestors alive over thousands of years are now leaving us feeling dissatisfied, anxious and depressed. Thanks to the rapid advances in technology and culture we now find ourselves faced with. The simple fact is we're living in an environment that our brains were not built to survive in. In this episode we're joined by Dr Paul Galsmith, an evolutionary neuroscientist author and visiting professor at Imperial College London to talk about his latest book, The Evolving Brain, an ancient tool in a modern world. He tells us how the pressures and goals many of us are now confronted with are vastly different from the challenges faced by our ancestors. The huge impact this is having on a mental wellbeing by excessively triggering our natural stress responses and shares some advice from neuroscience we can all use to navigate the trials of modern life more healthily. So welcome to the podcast. Thanks so much for joining us. Absolutely pleasure. So today we're talking about your book The Evolving Brain, an ancient tool in a modern world. So these days sort of mental conditions like depression, anxiety, burnout are quite alarming rates. I think something like half of us will suffer from them at some point if not more. And you argue there were a point now where our brains are actually struggling to keep up with modern life, culture, technology, etc. So let's first off briefly lay out that thesis. Yes, so our brains reflect the evolutionary root which has been taken, the developmental underpinnings reflect the layering of complexity from a basic cell up to a basic brain and onwards. And if we think about the time course of that, two billion years for a basic cell, another billion for a specialized cell, 500 million for a worm, which is sort of largely brain. So that's when brains really get laid out 300 million years for mammals, 60 million years for primates, for homies, up he ends for us, it's a matter of a few hundred thousand years. So that's less than 0.01% of overall development. And then we've just had this rapid change in the external environment over the last, not just a few hundred years, but the last few years. And we're left with a tool inside our skulls, which is designed for a world dramatically different to the one that we now find ourselves in. And that helps explain the paradox that we live in that we have so much, so many tools, so much material abundant, so much knowledge. And we can edit genes, we've got AI, communicate around a globe in an instance. Yeah, as you say in your introduction, there's an epidemic of stress, anxiety, and depression. And it's a paradox. And many people, and this is part of the motivation for writing the book, many of my patients blame themselves. They think there's something they're doing wrong. And one of the key messages is, is not your fault. This is a reflection of the evolving brain being optimized for a different world. So the book sort of broken down into chapters, looking at many of the different aspects of this sort of, I don't know what you call it, push and pull effect. So let's have a look at some of those. So first off, it's motivation. As you say, we're all the products of, you know, count this years of evolution. And you know, our ancestors were successful in finding the essentials of life, you know, food, shelter, successful in pro-creating. And you know, they must have had a strong motivational drive to do so. So sort of physiologically or neurologically speaking, you know, what's providing that drive? Yeah, it's a really, it's a really important question and a baseline for everything. And the book is ordered logically. So it's taking to the journey of how the layering of complexity occurs in the brain. And it begins with motivations to do things. So ultimately, there's only one basic difference between a plant and an animal. And when people think about this, so yeah, that's probably photosynthesis. But that's not the case because we make vitamin D from ultraviolet light in our skin, nor is it sort of social grouping because trees have complex social networks through mycorrhizial strands under the ground. What it comes down into is movement as in changing location. And so everything ultimately comes back around coordinating and optimizing movement towards a goal. And the critical bit there is towards the goal. So the brain rewards us with a positive feeling if we are making successful progress towards something. And the primary fuel of that is dopamine. But critically, it is the journey rather than the destination because nature never envisaged us just having things arriving our laps. And Pavlov's dogs are delighted and would celebrate when the sausage just arrived in their laps. But they would still go absolutely stir crazy if they didn't get to chase sticks. And when you think about what those goals then became during evolution, there are sort of two broad aspects. The first is sort of fairly simple short-term goals. These would be around building shelter, finding food, chasing predators, escaping prey, and also functioning in a group. So for our ancestors being excluded from the group was lethal. So we've evolved a set of control mechanisms incentives to optimize group function and small group function. These are all ultimately goals that when a successful they give us our maximized dopamine release when they're not successful, then there's another tool that evolution has cooked up to encourage us to disengage from unsuccessful or predict to be unsuccessful goals. And that starts to get to one of the major problems in modern life. So we'll have a look at goals which you talk about a lot in the book in a minute. But let's stick with dopamine. So you talk about dopamine pathways. So I bet most people have heard of dopamine. But what actually is it and what function does it play in our brains? It plays multiple functions. So one of the things that nature does is it reuses the same thing over and over again and it will slightly modify its use. One of the roles of dopamine which is very important is signaling that something is more desirable. So it's like sort of a playing that game as a child. Are you hotter or colder in terms of moving towards if you're blindfolded? And dopamine is saying you're getting warmer. This is good. So it's a thumbs up. And that then triggers a positive memory. So it's saying this activity is desirable. So essentially this memory of doing this is good. So it's got an important role in memory as well. And not then links to movement. So it's saying this movement is a desirable movement. So it's absolutely key. As you can see with Parkinson's disease where the core abnormality in Parkinson's is a drop in dopamine levels and you see that manifest with a poverty of movement. Yeah, that's fascinating. So I think a lot of people won't be aware of that even though like Parkinson's unfortunately these days it is relatively common. Yes. Yes. So it is the motivation to move which is lost. So that positive drive towards a target. And you see this in clinic when you ask a patient to stand up from the waiting room and come through. So that quarter action is not responded to in the normal way. But in our everyday lives we are constantly having dopamine released in everything we do to drive us towards something which overall helps us survive. So if I go for a cycle the ultimate goal is to get around the full circuit. But I've got lots of intermediary goals getting to the end of the road getting to the next lamp post every single turn of the pedal is a sub goal which if successfully completed and in action is bringing a little bit of reward which I would not get if I just got a taxi around. Yeah. So you touched on something that you talk about in the book which is sort of top level goals and sub goals and use the analogy there of cycling. But let's have a look into that. How does that work like with it in our ancestors and a sort of ancestral brain if I can say that. Yes. So one of the things with SAP Yenner's development is our ability to sequence more complex goals. So multi-step goals. But if you look at our ancestors you think what they would be as said before it's still the hunt, the collection of food. the social in relatively small groups. So these things play out over a relatively short time period hours or days, more predictable, critically with reliable feedback. Now what goals do we have in modern life? It's get the career progression, the new title, a bigger house, move to a more desirable location, get an academic paper published. These are long-term abstract, often conflicting goals, without reliable feedback or we may get feedback that we are failing. And that leads to both stress and melancholy. And it's an important thing to understand why. So nature has given us a tool to assess our progress towards a goal and motivate us to disengage if it predicts that the energy expenditure outweighs the reward. So imagine a deer, it's winter, it's really hungry, but it knows that there's some food, it thinks a couple of valleys away and it sets off, but the weather closes in, the ground is really swampy, it's making very slow progress and it hears some potential predators. The brain may calculate disengage, return to base, and you associated emotion with that is melancholy, just a tiny whiff of it. Now what do we do in modern life? We've got society, our peers, our parents, others saying keep on pushing on, you are a failure if you don't achieve this goal. So we keep on trying to reach it, we're not getting signals or we're getting negative signals, you're not being successful another rejection or failure to achieve something. So the brain is applying the break, but rather than disengage and starting something new as we would have done, we've got the accelerator on at the same time and that is a key reason for modern dissatisfaction. So let's stick with this idea of melancholy or low mood, something no doubt everyone's experienced at one time or another. And this can like sticking with motivation as well. This can lead us to losing motivation, you know, quite severely in some cases. And you mentioned there this concept of disengagement. So in the book you talk that there are four phases of disengagement. So can you talk us through those? Yeah, so when met with a challenge, the first thing that the brain does is activate us more, gives us a bit more energy. So we've got a stress and energisation response, a dynamic control system in the body controlled by the brain, which happens to us all. So we all get a massive stress response whilst we're asleep. Just before we wake up, there's a big big rise in cortisol levels to primus for a day to get everything ready. And it's a bit like for those older in the audience, when you pull out the choke and the car to allow it to start. So that's what's happening. But if you then are on your hunt and you come across some fallen rocks, you've got a clamberow, the something to outrun, then you'll get an extra squirt of both cortisol and some adrenaline into the system. So it's like switching our car into sports mode, briefly, some extra petrol into the tank, into the engine to fire it up. But typically that would then drop off quickly as you've overcome the obstacle. Modern life, we've got constant challenge. So the constant stream of emails or the poor worker in the call center with the red flashing lights, there's still people waiting. So we're being activated with that early phase, as you mentioned, of the stress activation response, redding us to outrun a lion when all we're doing is pressing keys on our keyboard. Then if we are still calculating that we are not succeeding, it passes from that activation and aggression response to the withdrawal. So that melancholy, which is a normal thing. So it is universal, saying disengage. And then if you do disengage and shift goals, then you can recover. The problem is many people don't actually truly disengage. So they may stop doing things, but they don't actually give up the goal. Yeah, so let's stick with goals then. And you talk about the prevalence in modern times is what you call unachievable goals. They've kind of knocked this process out of balance. So can you give us some examples of what that looks like? Yeah, so we're now rather than I'm going to get some food and I'm going to build a shelter and I'm going to have a mate and there's only a choice of three in my group. We've got these complex goals that are given to us by our parents and our peers are now from social media. With this comparison with millions of perfection and one of the broader goals that we have as a social species is the need to be validated. So receive validation and status. So signals that we are part of a group, but also that we rank more highly within the group. So there's sort of two interlink and they're very important. Now that is a it's a major driver behind success in society or society's success. So it helps drive progress, but it can be really unhealthy for the individual. So there's this, you know, what is good at community or country level may be very bad at other personal level. And as an example, look at some of the politicians or incredibly successful people in the media, their millionaires, they've achieved everything, they're great sportsmen and they're just desperate, absolutely desperate to get an honour to be a sir or a lord, to get that recognition, that status and they get really upset about it and some get not just melancholy, but they get frank depression. And you think no, it's ridiculous until you understand how the brain works and then you say, okay, this logically makes sense. And actually when you look at most of us on our everyday lives, we have similar to a lesser degree in terms of the absolute level, but it's a sort of a similar needs for acquiring those trinkets that recognition. So this is sort of based on our perception, I suppose, if progression. So you hear a lot of people suffering from loma or even clinical depression in some cases saying they feel they feel stuck, unable to move on. Yeah, that's a really astute point you raise because until you move on, you can't really cure. And sometimes that's forced on you. So as an example, child bearing, there are a group of middle aged women who understandably become really upset because they want to become pregnant and can't. And not as they approach menopause, their emotional distress does become more intense, but an up to menopause, it lessens and may go away completely because the possibility is now gone, it's done. And I see this clinically as well. Sometimes, unfortunately, when you diagnose somebody with a terminal illness and there's great sadness, obviously, but sometimes they say it's sort of punctuated by moments of relief because they don't have to deal with all of the crap anymore. The goals are removed from them. So it is important to know when to be to display grit, which is important to succeed in life and how to manage that from a psychologically in a healthy way, and then when to give up and giving up is not an act of cowardice, it can be an act of self-compassion. So let's go back to the sort of evolutionary idea. And in the book, you sort of make a difference between our core brain and our outer brain. So what do you mean by that? So the core brain, I mean, and I would say that all animals broadly have the same structure, the same layout is just it's scaled to different in different ways. So we've just, the more primitive animals still have a frontal cortex, it's just tiny compared to ours. So if you think about things from a developmental perspective and developmental biology, an evolutionary neuroscience, so two sides the same coin, the basic structure of the brain is like the trunk of the tree onto which, and that's what I refer to as the core, onto which we've got the outer branches and leaves, which is the complex, the interface with the modern world, and which reflects everything we've been exposed to since birth. So in this sort of evolution that's happened over thousands and thousands of years compared to the rapid cultural evolution, it's led to some flaws or what you even call in the book Achilles heels, the in the way that our brains approach these challenges and problems. That's right. And there are many. We can talk for hours from the way we process information and optimize which leads to traps in terms of our certainty about things to the goal setting going to rye as we've talked about and propensity to depression to anxiety and the social structures which can trap us in depression and excessive anxiety which very topical at the moment and UK with issues with school refusal and it gives things like anxiety and this sort of surprises people actually sometimes the brain has given us a set of tools to optimize things. Evolution is not interested in our happiness. Happiness is but one tool that it uses to achieve its ultimate goal which is for our genius to be passed on because without our genius being passed on the line would have died out and we wouldn't be here to have this conversation and as examples of some of those tools it is pain, anxiety, happiness, sadness and pain as an example I've got occasional patients who are unable to sense pain rare genetic conditions you can also get it with leprosy or in the old days syphilis they die prematurely pain is useful. Now that doesn't mean I don't want a general anaesthetic when I'm under a surgeon's knife so it's about the right context and similarly with anxiety and I've got quite a few patients who I wish were more anxious because anxiety motivates us to stay out of trouble if it's in the right context and the right degrees it's like a smoke alarm where we put up with a smoke alarm going off with burning toast to guarantee it will go off with a fire and similarly it's a key survival benefit for anxiety be triggered by a rustle in the leaves if it might be a predator but in ancient times the threats were much more predictable would play out quickly and we'd calibrate that alarm but now in the modern world we've ever changing breaking news stories tangled relationships at work faceless bureaucracies that we've got to battle with every day and are imaginative frontal lobes that can concoct up complex threats and we're not calibrating in fact modern society may actively discourage us from calibrating so if I had a fall out with a friend 20,000 years ago and I'm feeling sad with drawn the next day I'm out on the hunt I've got no choice I get instant rehabilitation, instant community service if you like how does that play out now I go to the GP there might be a long wait get put on an antidepressant which numbs things a bit referred into cognitive behavioral therapy another way to four to six weeks and then I get various sessions all of the time I may have completely withdrawn from society and doing the very thing that would help improve my situation and I suspect that this also underpins a lot of the challenge that happened during covid when children were removed from school and it is entirely understandable that they would be anxious to go back but the longer you leave that then the greater the problem becomes so you have these vicious circles as many vicious circles that modern society is created and which we we slip into can we do anything to sort of arm ourselves against this to spot them before they're coming like they say prevention is better than cure you know because sometimes these issues for some people they will go for them here in a couple of days or whatever but for others they'll linger on and they'll become clinical issues yes so this is the ultimate aim of the book not just to be an interesting read although I hope it is it is to give practical advice to give people a toolkit to face all the challenges of modern life and do the things alter the way that we think about things so we are more resilient and happier so how about the idea that you talk about adaptability so this is really interesting on several levels because for quite a long time I remember when I was in my mid 40s now when I was younger they said they're no you can't grow new brain cells you know they you're just born with the same one that's it which is of course being proof false now but our brains are incredibly adaptable they are they are incredibly that is that is our major success as a species and as primates it's the fact that we learn after birth so most brain growth occurs out after birth and there's a practical reason for that that if we had adult brain sizes we emerged from the womb we wouldn't get out of the pelvis and so we see this enormous growth and then we are nurtured by our parents and protected whilst we learn many things but that happens throughout life and the the basic aphorism of neuroscience is neurons that fire together wire together that is the learning process involving dopamine as mentioned earlier and we learn even in old age I'm a bit older than you and I'm learning a new language that is altering my brain it is not a one way street of a brain degeneration from your 20s now some of that is synaptic plasticity and altering the synaptic weight so the strength of the connections between the nerve cells but encouragingly there is recently good evidence that we can form new neurons new nerve cells in the hippocampus a bit of the brain which is particularly involved in memory formation also in the olfactory cortex involved in smell but in the hippocampus importantly and things which seem to promote that are physical activity and also cognitive activity another I think broad rule I would state is use it or lose it applies not only to our muscles our bones our cartilage but also our brains how about the idea of novelty you know it's seeking out new experiences good for our brain health it is it is so it's both maintaining what we have been exposed to because the brain if it thinks a memory is no longer useful it will gradually downgrade so merely repeating previous exposures is important and one of the key roles of our brains is to coordinate social relations linked to the social brain hypothesis of Robin Dunbar and again there was sort of evidence during covid of an acceleration and dementia rates because people were not getting the same social interactions that they were used to in the same way that neurons that wire together wire together neurons that wire together die together so you do need to keep on stimulating even better if it's novel stimuli and going into the adjacent see of what you or what the pathways have already been established to do so we've kind quite a lot there already and there's an awful lot more in the book so I'd encourage anyone listening to check it out but sort of by way of summary obviously we've laid out the we're in this situation where our brains have evolved over thousands of years and our culture etc is evolved very rapidly over the last couple of hundred you know so is there anything we can do to just sort of make that dichotomy a little bit easier to manage just to sort of cheat sheet there is there's a whole set of things so practice points which I've never counted them actually in the book but it's probably a hundred or so in there there are many and you know broadly I really hope that those who are in a position to affect change in society and our environment will become more enlightened and do so but until that time we need to alter the way we think about what we do and how we interact with the environment and how we behave and that will make an enormous difference because I've seen it happen in my patience in terms if you have to sort of crystallize everything down to a couple of things if you could only take sort of one message away it would be do stuff both social cognitive and physical is really important the most reliable way to get the dopamine flowing make those goals achievable stretch is good but achievable and try and get signals that you are making positive progress towards those goals and if you're not getting the right signals just think about it differently and focus on the social side of having a positive group with which you interact because ultimately as a social species the key goal that we need is to have meaningful reciprocal relations with a [BLANK_AUDIO] more group of reliable friends and to few people have enough. Thank you for listening to this episode of Instant Genius brought you from the team behind BBC Science Fakers. That was Dr Paul Goldsmith. To discover more about the topics we've just discussed, check out his book The Evolving Brain, an ancient tool in a modern world. If you'd like to what you just heard then please do consider subscribing to Instant Genius when you're preferred podcast platform. If you'd like to see our guests and hosts in person then why not check out our YouTube channel at ScienceFocus. The current issue of BBC ScienceFocus magazine is out now. Pick up a copy wherever you buy your favorite magazines or download us on your app store with choice. You can also find us on Apple News or online at sciencefocus.com.