Instant Genius - Busting the biggest myths in neuroscience

Episode Date: September 11, 2025

Relatively speaking neuroscience and psychology are young fields of scientific research that only really got going over the last hundred years or so. However, during this time several stubborn myths have arisen that, zombie-like, just don’t seem to go away. In this episode, we speak to neuroscientist, best-selling author and long-time BBC Science Focus contributor Dr Dean Burnett. He tells us how much of our brain we really use, explains whether polygraphs can really tell if we’re lying, and explains the real difference between our left and right brains. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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I'm Jason Goodyear, commissioning editor at BBC Science Focus. Relatively speaking, neuroscience and psychology are young fields of scientific research that only really got going over the last hundred years or so. However, during this time, several stubborn myths of a result. that zombie-like just don't seem to go away. In this episode, we speak to neuroscientist, best-silling author, and longtime BBC science focus contributor, Dr Dean Bennett. He tells us how much of our brains we actually use,

explains where the polygraphs can really tell if we're lying, and explains the real difference between our left and right brains. So, Dean, welcome to the podcast. Thanks so much for joining us. Thank you for having me. Much appreciate it. Oh, you're welcome. So today we're going to be busting some.

some common and pervasive myths in psychology. Let's start with a big one, and that's that we only use 10% of our brains. So first off, where does this come from? It's hard to say. There's a few sort of different sources I've found, but one particularly sort of, plausible seeming one, is that it's from like the turn of the 20th century when people started investigating anatomy and exploring the actual science of it. And it comes from some studies where someone had some.

top of their skull removed and was just being prodded with electrodes to sort of see what parts of the brain and do what. Now obviously this is a very, very rudimentary method of testing the brain, but what I read that sort of 10% of the surface of the brain, if you poke it with an electrode, the body does something. So it's like 10% of the top of the brain is involved in voluntary muscular control, which, you know, that sounds about right. Then the motor cortex is quite small, quite sort of restricted, but there's also lots of

different reflexive bits, but the brain does more than that, a lot more than that. So that's not exactly helpful, you know, but it's also a very, you know, helpful myth for those who want to spread, you know, we've only just scratched the surface of what our potential is. And therefore there's lots of grey area there for people who have, you know, like, abilities on their mind, things like that. So, you know, you can see why it stays around, but that's, so, I think that's the basis of the myth that I've encountered.

There may be others, but it's always a misunderstanding of what counts as the brain doing something. Yeah. How about sort of how much of our brain are we using at a single given time? You know, is that sort of fed into this myth? In a sense, but it's also in a very realistic sense, the 10% is actually quite optimistic. It's like an overestimation. Our brain, you know, it's the most energy demanding, hungry organ in the body. It makes up 2% of our mass but uses like 25% of our body's reserves.

Just staying alive. So, you know, in terms of evolution, if we didn't need all that, we wouldn't have it, simple as that. If you find some species which evolved an organ, which is like 10% useful, negligent redundant, but also consumed all the energy, pointless exercise, you know, that's not a good survival trait. Like that, it's like taking a space shuttle, like, and then fill in it, like, it's full of rocks. Well, why he was on that? That's just pointless. Someone else who doesn't do that, it's going to succeed. All the brain's tissue is doing something if it's just staying alive, you know, it needs to stay active to exist.

When brain stops doing anything, that's essentially dead. So it's a very quasi-stable setup. Like it has to keep doing something. There's at least baseline activity. So the brain's always, every part of the brain is always doing something. It's always active. When it comes to sort of being used, being functional in terms of like, oh, I want to actively do this now. I want to focus on this.

I want to think about this. I want to use a lot of, like, in a traumatic situation, your memory system boost. Yeah, when you want to raise activity and do something, because of the way the blood supply, the circulation system of the brain is so restricted because the brain is so densely packed in your head. Human brain is any bigger, a head after bigger, and that would be very problematic for

the birth and process, for just maintenance, or just being able to stay alive because it's too demanding, so on. So we're at a real sort of real fine balance between how much brain we can have and how big our heads can be. A part of the result of that is the blood supply of the brain is quite limited. You can't shove pipes into a supercomputer, it's just not going to happen.

So the brain has a sort of limit capacity to shunt resources around. Some estimates I've seen say that, yeah, you can sort of use way more than 10% of our brain, but you can only actively accelerate, amplify the use of like 3% at once because we only have so much resources

go into it, the rest is needed the brain to stay alive. Example I've likened to two is like a restaurant with a hundred tables, but only like four waiters. And, you know, like those could work as hard as they can, but you never have more than four tables being served at once because it's physically impossible. And that's sort of

how the metabolic setup the brain works. It's always there. Everything's sat down, everyone's seated and the restaurant's working. If you want to actually do something, you have limited resources to do that.

And that's why we can get so easily overwhelmed and lose focus or get distracted because it doesn't take a great deal for us to go, what was I doing? And then you have to shunt it somewhere else and then you've lost the previous thing and so on and so on.

So 10% would be quite a step up in that regard. But yeah, we are using every part of our brain. just all the same time, if that makes any sense. So, you know, as ever, it's a more complex situation than the stubborn myths would have as believe. Yeah, so let's stick with the brain. I'm kind of my job. So I'm, yeah.

And, you know, a lot of people say, oh, I'm left-brained or I'm right-brained. And this seems to not want to go away as well. So what do we know about that? Yeah, the left-brain, no, left-brain, analytical, right-brained, artistic, creative, that's a very stubborn myth as well. Like, not so much anymore, but there's a period. when if you went on Facebook for like 10 minutes, you've got to like, you know, stare at this revolve and statuary.

If it turns left, your right brain, if it turns right, your left brain, like it's an ambiguous stimulation. That's a whole other thing. Yeah, I mean, I first looked into this. I thought like, oh, that's just nonsense. That's easily debunked. But frustratingly, somebody was here to debunk stuff, there is an element of truth to it.

The brain has two hemispheres. Like, it's like two walnuts glued together, you know, and they do have, you know, each side has a paper campus and amygdala, like a, like a, like a simple low. So each side is like corresponding, but it does seem to be functional differences between the hemispheres. And this is a sort of very general summary of it. But by and large, the left side of the brain is all about big picture stuff, you know, the distalp.

Like what's the whole situation, whereas the right side is the specifics. So like the left side sees the trees, the left side sees the forest, the right side sees the trees. And we see that something like the left side of the brain, the sort of parietal cortex, seems to handle more language, words, sentences. The same part of the brain on the right side seems to be more about tones, sounds, so the individual elements of it. And you can sort of see why that would mean,

like people think the right side of the brain is more emotional, because emotions would be more fundamental than sort of abstract concept thoughts, because they evolved first, there are more sort of baseline brain function. And then you can sort of see, like, if someone is thinking about the whole picture logically,

then they would imply, the left side of the brain more than the right side, where someone is more impulsive, reactive, and, like, flights of fantasy type stuff, not, you know, wants to see what's where things go in, then, yeah, you can see that being a more creative output, a creator, but, but it's also like, that's still a very, very, very crude,

overgeneralization of the situation. Imagine someone, once a creator, like a masterpiece, they, you know, a sort of sculpture from scratch or a huge mosaic, they would logically have to see the big picture, you know, to put everything together, which is very much in this framework, a left brain process. Or someone was like, you know, a very fundamentally analytical. Once to look at any individual detail, like in a spreadsheet or individual elements or something,

that would be like the individual elements, which would be a right brain process. So while the general theme is, the left brain is big picture, the right brain is fine detail, how that is expressed, how that comes across is far more variable from situation situation person to person, context to context than this simple your left brain, you're a nerd, your right brain, you're away with the fairies. That's a very, very crude over-summarization. But, you know, it's a simple one.

It's a simple answer which people like and stick to. People like, oh, yeah, I'm like that because I'm left-brained. I'm like that because I'm right-brain. People just like that a simple explanation for things they do. But that's almost on the verge of, well, yeah, of course I do that. I'm a Sagittarius, which is like, I'm not entirely sure that. All right, fine, fine.

You do you, but, you know, that's, yeah, it does edge into that. territory very quickly and it's not really helpful in that regard. So let's move on to another one which I find really interesting that you see everywhere in popular culture, in movies and in certain panel shows from the 90s with dubious moral standards. Yes. And that's the polygraph, the lie detector. Yeah.

So what's the theory behind this? Well, I think there's a certain misconception in the wider culture that a polygraph, detects actual deception. So it measures what you're saying and can detect untruths or inaccuracies or dishonesty. It can't do that. There's no technology around which can do that. You can't analyze someone's speech output and say,

ah, this one is inaccurate or actively deceptive, which is what the point of it is detecting someone lying. The principle of it is, a polygraph means basically measures lots of things, lots of measurements. It's measuring your, body's like autonomic activity, the baseline activity of your body, like your heart rate,

the skin conductance, like your pulse and blood pressure, things like that, which alter in response a lot of things, but in this case, particularly talking about stressful stimulations, you're being aroused, not in the explicit sense, but in the sort of fundamental biological sense. Your nervous system activity is increased in this respect. So the theory is that when you lie, when you're telling a lie, you are stressed by the act of lying, and your body responds to that. And then when you're being attached to a polygraph, that detects this arousal response you have in response to lying,

and therefore whoever observes the output of the polygraph can tell that you are being deceptive, you're lying. And, you know, it's a straightforward theory. It's a certain, you know, there's a logic to it, and there are people that they insist that it does work, it's a well, you know, it's a documented process, but there are far more scientists who insist that it's not a viable tool. It doesn't do what it says it does because, well, yes, there are certain situations, occasions

when lying will cause a stress response. That's not the only thing that causes a stress response. If you had a list of everything that causes a stress response to the human body, lying would be quite low down that. So you actually have to appreciate that the research which sort of supports the polygraphs work, girls usually done in labs where people have turned up there voluntarily. You know, in a very sterile environment, like they know there's no consequences. It's just, I'm just volunteering for the study.

You know, they ask you, you know, a few questions. And the usual procedure is you ask someone very forward questions, which have no bearing anything like is your name Fred. And you say no, unless your name is Fred, in which case you say yes, because, you know, you basically tell the truth. And then they get a reading of, okay, what's this person's bio-levels look like when they're not lying? So then when they do lie, they can see where the spike happens, oh, this is a lie. That is a very sort of neutral, safe environment.

Now, where did the lie detectors normally occur is like police interrogations or, you know, on national television, on dubious reality shows when, also there, where there are big consequences to, well, either lying or telling the truth. So usually, like, you've been interrogated by the police as part of a suspect in a criminal investigation. It touched her a polygraph. They say, did you kill that guy? I mean, that's a stressful situation to be in, regardless. of whether you did it or not.

Also, police interrogation tend to not be neutral. They are very sort of leading. You know, police do their jobs, but they're not scientists. They're not doing this by the book in that respect. So, like, there's so many different things which kind of really affect the output of a polygraph. If you, you know, a caffeine spike can have, like, a drastic effect on bio levels. And every time you see this producing interrogation, someone's like a coffee beforehand. Which is totally fine.

Logical. Like, yeah, I need a coffee for this. But then that's going to throw off all your levels. And the very active interrogation, so like, is your name, Steve, and then, you know, in a police station being surrounded by, you know, people who could, who will decide your fate? If this test goes badly, you could go to jail. And that's, you know, whether you're guilty or not, that's going to sort of be a really stressful situation.

And, you know, this is why, I think, but nothing, anywhere on earth are, you know, polygraph results permissible in court, because the science bearing them is simply not supportive of it. a lot of the time it's basically just like shaking a magic eight ball. Are you guilty? All signs point of yes. Sorry, mate, the ball has spoken. That's not a legal system you can rely on. And there are some approaches like in Japan have a different approach.

They're a bit more sort of accepted there because they have, well, one of methods they use is the interrogate. It's not interrogation. It's like an interview by someone not involved. Like I said, they don't know what the situation is. It's a neutral person. and the person in the photograph has multiple choice answers to questions

some of which pertain to the crime and which don't so like you know in this crime that happened was the weapon axe knife, hammer and they answer them

you know basically it's not like the answer is a response to seeing the correct answer it's like oh no like it was an axe like spike

so that's a bit more nuanced a bit more you know robust but it's still not a reliable thing so yeah like but it's a very compelling concept, a machine which can tell whether you're lying.

There's also a big industry behind it, people who offer this service. It can be a useful tool. How someone reacts when attached a polygraph, when they think that you can tell their lie in, that can be useful information in and of itself. It's just not, you know, per court misinformation information because it's not robust.

It's a trick. And that's not really, you know, okay, fine, you can find a way to use that. Fair enough. But in terms of the proper robust evidence, and no, irrefutable data, they're not really any good in that respect. Ambition comes in all shapes and sizes. At First Citizens Bank, we roll with your goals because we're built for what you're building.

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name audio creates systems that deliver exceptional sound and unforgettable listening experiences at home. Try it for yourself at a focal powered by name boutique. Visit focal powered by name.com for more information. So you mentioned earlier the kind of revolving test that comes up on the internet, or you left-brained or you're right-brained. And another thing that comes up quite a lot on the internet and this sort of thing is, It's personality tests.

So where do these come from? And, you know, can we learn anything from them? There is a big industry behind personality tests. Personality tests are of personality studies, like a viable psychological field. There's a lot of work on into them. It is a very tricky one to sort of provide any sort of concrete conclusive data about. because, you know, it's, what do you define someone's personality and what are the results of it? I mean, one of the earlier books I likened to, you're trying to study the anatomy of a cat

by picking through the hairball that's coughed up. There's some information there, but are you going to sort of subtract, okay, this hair is here, so that must mean the cat is intestine shape. You know, it's not really something you can, it's a lot of steps between what you've got and what you're looking for. A bit of, you know, a lot of data, a lot of, like, factor analysis can help you. find certain traits, like the Big Five personality tests or, you know, the certain elements, like the introversion, extraversion scale, those are things which people sort of do find useful.

But, yeah, there's a known, the famous one being the Myers-Briggs personality test, which is very familiar, if it's a lot of people's bio, like I am an MBTI or whatever that means. But it's not actually based on any useful science. It's put together by two women who were, like, at the time, housewives. weren't like qualified scientists, they became recognized as personality experts by putting this together, we've talked on Myers and Briggs. And, you know, what it does, it gives a very sort of, straightforward and easily conceived metric of an individual. And people want that. People want to say,

like, oh, this person is, scores this on the test, therefore they are that sort of person. Here's how you deal with them. Here's how to interact with them. This person scores this on the test. That's a different person, you put them over here with these people. So it puts a, I easily understood framework on individual humans, which is really useful for managers and people overseeing, like, you know, students and stuff like that. But it's not based on any sort of hard or robust science. It's not even reliable in the sense that someone is, they use a lot in interviews now, actual workplaces.

You must do the Myers-Briggs test and the employers do them. And the questions like, are you good at work in the team? Now, this assumes that every employee you, the potential employee, who fills one of these in, is completely and utterly honest at all times, you know, whether without a polygraph, and, you know, totally clueless just about what the agenda of this is. You know, they're saying, I must answer correctly and I don't, you know, I'm totally in a way of the consequences. But if you want to get a job at a company and they say, are you good at work in a team? No, no, no, I hate other humans.

No one does that. Yes, I am. Like, it's all like, you know, if they were totally passive, it might be something. use, but then they won't be. These are people who have their own lives and autonomy. And personality tests use in this way assume otherwise. They argue that, no, everyone who fills these in is being totally honest and never changes personality and is the exact same in every individual situation, which they're not. Even just nowhere near that simple. Even if you do find someone who seems to be consistent, they have their own internal life, which cannot be measured by personality

tests or just multiple choice questions. They have a lot going on upstairs because we are incredibly complex entities. And personality tests of the sort of more commercial sort, they really try and hide that fact. They try and ignore or even suppress that eventuality that people are complex and do not behave according to metrics or frameworks, which would make life much easier for managers and leaders and stuff like that. But that doesn't mean it's true.

It's because people want it to be true. But it is a very compelling idea which makes it very profitable. I mean, I actually have been told that, because I wrote about this for The Guardian back in 2013, but why these things don't work. And I actually did, you know, the friend of mine was working for a university psychology department at the time. And the vice chancellor of the university said, I've just spoken to them, you know, the people who supply these tests. And in exchange for like many millions of pounds, we're going to do them to all our students. So we know we get the best students with the best personalities.

And obviously, like, psychology department is like absolutely not. We're not doing that. You know, that completely undermines their credibility. Like the physics department or the astronomy department saying, yes, but are you satirious? We only accept Leo's. Like, well, that would be absolutely mind-bendingly dumb for a professional science course. So they had to put the kibosh on it and use my article. Like, look, see, read that.

That's what it is. So I know I cost the people who made it a lot of money at some point, which I'm personally quite proud of and I won't do it again. But, you know, it's that sort of thing. Like, it's an industry now and you can't really, you know, money talks, even though it's not telling you anything useful, but it does. So, yeah, it's a very compelling myth which a lot of people have bought into, and therefore it's still around and isn't going anywhere.

So how about a sort of similar thing that often pops up in movies and pop culture? And that's the inkblot test. Ah, right, yeah, the Rorschach. Yes. Yeah, obviously, Rorschach. They'll obviously, the Bannon Moor's superhero Rorschach, which is a whole other thing.

But, yeah, the Rorschach test is a really, really old psychological test back in the very early days of psychoanalysis when Freud invented the concept. and for a while it was kind of a free-for-all. You know, like Freud's ideas were quite groundbreaking and, you know, very sort of influential haven't really been sort of proven by later science.

But it's one of the things, because he was so fundamental and so profoundly influential, people sort of think like, well, he was right and therefore we must stick to his ideas. But that's sort of like saying, you know, these days you should fly abroad on the Wright brothers plane because, you know, they meant it. They did, but we moved on.

We have enhanced the design since. But no, no, they invented, therefore, we should always stick to that. I don't think, I don't want to go to France on that. That sounds like a bad idea. But it's that sort of, you know, approach sometimes. But the old inkblot-Rorschach thing, it is, in a sentence, it works. You see someone like, hey, look at this completely random, you know, sort of assembly of black and white colours in this totally pattern.

What do you see? And you arguably are getting something useful, on that, or at least something valid. I see, you know, like blood or I see, like, you see someone in a negative mindset or in a positive mindset, or they go to a certain, you know, someone keeps saying and saying, I see, mother's face, my mother's intestines, my mother's like,

okay, I'm getting a theme here. But the problem is, it's completely non-reproducible. Like, there's no sort of metric to it. There's no sort of, like, established, okay, 10% people will see it like this, or like every normal person will see this, but then that someone who was, psychological issues, we'll see this instead.

It's totally subjective. It's totally sort of based on the individual. And therefore there's no consistency to it whatsoever. So it can't really be used as a diagnostic tool in any sort of, you know, scientifically approved way because, you know, someone looks at it said, oh, I see butterflies eating mud. Okay, good, no one else has ever said that.

No one else has said it again. But you said it, great. What do you do with that? You know, what does that tell you? And there are certain schools of thought in psychology and clinical psychology would say that you should have a bespoke approach to every single patient. And rather than sort of say, okay, rather than sort of fit the patient of the diagnosis of the patient. So like, you know, you have signs of oppression.

You have signs of anxiety. You have signs of bipolar disorder. You have signs of schizophrenia. Like these are all, people can manifest all these things. But, you know, they don't know, which one is the most common? Let's put them in this box. And that's some people argue you shouldn't do that. So a test like this would be.

So, well, just see what they say. It can be handy in that respect. But again, it's, there's nobody anything you can do with it in the scientific sense. It's just like, okay, you saw a random pattern and you said you saw this. Great. That's maybe useful, maybe not. How do you tell? It's a very sort of, it's a very old-school approach where you could just wing it.

And these things, wing and it is frowned upon in mental health care because, well, I think for obvious reasons. Yeah. So another one that's, that I've heard a lot about recently, which, um, sort of I've got a dog in this fight because I'm in my mid-40s and it's that we're least happy in our mid-40s where's this come from?

Yeah, having just arrived in my mid-forties myself I had my birthday like a couple of weeks ago and two days after my birth my ankle just went. Oh, there we go, that seems like quite a cliche doesn't it? Yeah, so I get that.

I'm not entirely sure how robust that is as a phenomenon is for like there's some sort of, you know, a switch was off in your head when you turn 42 or whatever and then you suddenly lack certain neurotransmitters or like your reward system gets missed exhausted. I imagine it's a consequence of, you know,

reaching that point in your life when you have perhaps the most responsibilities and you know, you sort of know you're physically past your prime, you start noticing clitches and aches and stuff where you didn't before. You know, people in their 20s and 30s don't notice that so much or if they do, they don't realize it's going to get worse, which is, you know. Also, like, 40 is, like, the midpoint, I think if you realize that people like, you assume, like, you live 70, 80 years, then at 40, you're like, oh, right, that might, this midpoint.

But I do think it's a, it's like to be a combination of things. There are cognitive issues that happen, like, you know, when you start at 40s or certain milestones, which sort of, then you sort of lose physical efficacy here, or if you don't work on it, you know, there's, you know, there's, you know, there's certain sort of steps throughout your 40s and 50s, which say, okay, this is the point we'll tend to experience a loss of this hormone or this particular thing. And, you know, especially when, obviously,

women have the menopausal thing to worry about as well, you know, perimenopausal, that sort of kicks in around this time as well. I know so many women my age who are just dealing with that right now, so that's obviously going to be a big part of that. When you're 40, like, people are 40 now tend to have kids and, like, they're teens, so that's work.

That could be a stressful experience, you know, So it's probably a confluence of different factors that happen at this point in your life, which will impact on your happiness. But it's not, obviously, it's not a hard and fast rule. There'll be plenty of people in the 40s who have never felt better, especially because these days you can, it takes a long time to get going in terms of career and life chances and stuff. So I know people in the 40s who have only just started having children and I just finally

got their career and they're very pleased. So, you know, it's, I think it's a confluence of things in the modern world, rather than anything particularly biological, but you know, could be wrong about that. There's so many different factors to consider. So let's go on to another sort of popular one in pop culture, and that's, we can use hypnosis to retrieve buried memories. So is there any truth in that? And, you know, where does it come from this concept?

Well, hypnosis itself is sort of a tricky one. It involves, like, you know, being a very, very, very suggestive state. So, you know, it involves sort of completely focusing on. the person or the hypnotist or the process to the point where, you know, your external thoughts are sort of missing. Normally, your mind's wandering here and there. You've got the background narrative going on with hypnosis. You don't have that. I think this is the theory anyway. So if someone says, you're a chicken now, but like that's what enters your head in more significant ways. I guess I'm a chicken. And then you act like, well, like I thought I'm a chicken,

I guess, that's the sort of thinking behind it. The buried memory thing is tricky. So there are ways which that could be feasible in that, you know, certain memories lurk in your brain and you can't retrieve them because they're not enough connections to them. Like, you've got this sort of distalt of memories which you use, which are you, you know, your identity, your understanding of the world, your expectations, your, you know, how you work things out. And if you've had a memory formed, which isn't sort of linked to this,

that very much, there's not many connections between like your mind, your frontal lobes and that particular memory engram. So it's harder to retrieve it, you know, to have a very certain route through it, you know, like, whereas like a memory of your partner's face or where you work or like your first childhood Christmas, whatever, these can all be very, very vivid. Because you've retrieved them many, many times, they're connected to many other memories, they're just there, easily accessed, you know, like the top of your brain. And the, the more buried ones are tricky to access. So it's feasible that you could be put in a hypnotic state to retrieve a memory.

But the problem of that is, A, recent research suggests that particularly obsolete memories, like all memories you never use, there's a good chance to be cleared away, like removed by the brain. The brain's always, quote-unquote, defragging because, you know, brain space is useful,

and a memory which doesn't use is a wasted resource. So, we talked about the resource stuff. So, you know, there's a certain biological process which clear up and use connections all the time. So a lot of memories will be just gone because we never use them, don't need them anymore. It's not like a sort of constant process, but it's like something in the background, constantly

tidying things up, creeping things away. So some of these memories will just be gone. While it's possible, I don't know, the hypnotic state could allow you to access that really old memory you can't remember anymore. Because the hypnotic state is so suggestive, it can also lead to confabulation, sort of creation of a memory.

So as you say, like, you know, You need to remember where you were when you were like 17 years old. It's like Tuesday afternoon, July 6th. You know, where were you then? And who has that sort of information of their memory? That's not how our memories work. We rely on like experiences, feelings, like landmarks. We don't actually have a timestamp on our individual memories.

But because of himnotice as being, like, you're so suggestive, you could feel and compelled to come up with something. And they're like, oh, I was in my bedroom doing, like, though, you may believe that wholeheartedly. And the other person, you know that person, you know, says, my God, see, we've got this now. How do you know that memory's real? How do you know that's accurate? Because unless you were there and have a detailed record of it, there's no way to know either way. You know, there's a lot of this happens in, like, you know, the whole false memories.

People try to, you know, interrogate, but, you know, interview people they thought were involved in, like, serious crime. and they end up saying, yes, they were. They have memories of this happening. And they never did. It was suggestion by the therapist who, you know, didn't know any better if we'd been extremely generous. But it still happened. You still have false memories a lot easier to create than people realize.

And, you know, but it's also how do you know, basically, how do you know someone like memory from 27 years ago very precise? How don't that's wrong or right? You weren't there. The whole point of this is you need them to remember and they don't. So tell me something from this time. And they tell you something. It's well, it must be true then.

That's not how it works. So that's why like retrograde amnesia that's over the one you get in soap proper It's very rare compared to Often it's often it pops up in media It's also very hard to appreciate Whether they're treating it or not Because someone said oh yes I remember this now

After like 10 years of therapy Like well do you like are you saying Do you remember it or do you think you remember it Because you've created this whole other memory For what you think should be doing These are all the things which are really problematic When it comes to retrieving memories And memory research

Unless you were there It's actually becoming easier as people like live their life online. So you can, you know, odds I know, 10 years ago, oh, there's, on Facebook, there you are, you tagged, that's what happened. So you can check now, which is actually makes it strangely better. But yeah, for a while, that wasn't really, how do you know, essentially? How do you know if someone's memory is real or not?

You know, memory's a lot more flexible and plastic and changeable than this sort of approach would suggest. And another one that often comes up is we're able to learn in our sleep. So if I play like an audio textbook or something as I'm sleeping, somehow some of that information will all absorb some of it. Where does that come from? There may be something to that in that when you're asleep, like your brain is still really active.

I think someone does the scan stuff. Your body isn't, but certain parts of the brain aren't really doing anything. But overall, like the energy that output of your brain is only like 5% less than when you're awake. Brain's always doing stuff in the background. It's always like, again, it's never off. There's never 10% and that.

But it's a tricky one because, obviously when you, it depends how awake or asleep you are. Obviously there are different levels of sleep, non-R-E-M-1-2-3 and REM sleep. And like you go through cycles of those every night. So sometimes, if you're at REM2, perhaps, if there's something playing in the background, your unconscious mind is still detecting things.

Your senses are still working to a certain extent. There's a thing called them the first night effect, which is why you never sleep as well in hotel or different house on the first night that's you in your own bed. because although it might be, it might be like twice the size of your room, might be much more comfortable, much more luxurious, bed might be much, much nicer, but when you fall asleep,

there's part of being going, this isn't my home, this isn't my place, I don't know what happens here. There's always that part which is always slightly sensitive to anything, any sound, any sort of change, like, this is not my place. So, you know, it's always a part of your brain

is just kind of aware of surroundings, at least at the earlier sleep levels. So if you were, you know, listed to something whilst in that sort of state, then yeah, I can sort of see you retain some information from it. And it's also particularly quite, it might be conflated with the fact that when it's you sleep on a problem, you know, if you can't think a solution, go to sleep on it and come back to me later, that is good advice because when you're asleep, your brain is sort of taken

right. Here's all the stuff I've learned today, is all my day's memories, and integrate these into my, existing memories to file them away. Otherwise, I'll just sit there being confused and cluttered. So when you sleep, your brain is more flexible. It's like it's open up all new connections to all things, so it's open up new pathways. And during that time, you know,

things like when you're sort of stuck on a problem, you can't think of a new solution. You're more chance of thinking of a solution when your brain is sort of sleepy state. You feel like think of dreams that all over the shop. And like when you wake up, you go, ah, I've got it because your brain is sort of more flexible now. New channels have opened up, new options have occurred

because you're in a sleepy state. And so there might be something to do with that, is it obviously when people, like, I can't figure this out, you go to sleep, wake up, it's got it. You go so, oh, you learn when you're asleep can obviously, that's a sort of like also a valid conclusion from that as well. Not quite the same thing, but, you know, when you're a sleep brain or like a tired brain

or just a welcome up brain is more flexible, is more sort of pliable, which means you can come up with new thought patterns, new ideas, new concepts. People who work in the creative field Sometimes we'll keep a note by their bed Not pad Because that's what your brain's doing like

Because two things are connected Which they wouldn't normally connect Because you're sleepy state And then, ah, great, an idea And then sort of pass out again And then you wake up the morning What the hell was that? It's a well-known thing

So I can see that would feed into that notion as well Yeah, I know that, I do that sometimes I wake up and I think I've got a great idea I'll go back to sleep And then in the morning it'll say something just like start a wheelie bin cleaning services. Where did that come from? I think that was wise.

Weeley great bargains. So let's finish up with one final one that doesn't seem to die, which is playing classical music to children or infants even makes them more intelligent. Yeah, you hear about that, particularly in the womb in utero. I think there is some evidence that suggests it does seem to be, you know, some sort of benefit from this. Problem of that is, it's obviously going to be really hard

to tell, like, cause and effect. Obviously, if you have babies who have played Mozart well in the womb, you have to wait quite a few years for you can measure their intelligence in any sort of feasible way. And even then, that's not including the fact that intelligence measuring

is quite a complex and controversial subject in its own right. So, yeah, so to do a cognitive assessment of a baby is hard. And maybe you can say, like, well, when do they reach their milestones? And I think there is some evidence suggest that if you do stuff like that, play classical music in the womb, you do tend to see

them advance a bit quicker than the peers who don't have that. And I think the rationale is that obviously when your baby's in the womb, the brain is developing there and then. And then it's been exposed to complex sounds, more complex than obviously typical background noise of the womb. One would assume, it's been a while. If the brain's being exposed to that, then it's could respond to it. So like if it's, if the developing brain has more complex sensations to deal with, then potentially it would then,

of the very earliest stages, develop the ability to deal with complex stimuli faster than brain, which hasn't had to do that. So it's responding to, okay, this is something I've got to deal with. I'll just log that in, see what that is, to see if that's useful. I don't know.

I'm literally not born yet, but you can sort of see at the very foundational stage, if that sort of experience is there, it would perhaps accelerate the brain's development to like, oh, this is complex stuff, I'm going to have to develop in this direction or develop this way to sort of deal with that, to process that, or at least to react to it.

And yeah, so you can sort of see how that might be a advantage for, you know, developing children and developing babies. So sort of like early exposure to complex stuff. I think they've tried with other stuff too, but I haven't seen the data for a while. But I think there is something to it. There's one of those, again,

people take the ball and run with it. Because yeah, there's a slight effect if you play classical music to a child in the womb, gone to do it, right, play Mozart every day, all day, you know, just strap a iPod to your waist, and then there'll be a genius by age six, because

well, that's not really... Also, Mozart as well, of course, was a child prodigy. Obviously, he was like four years old and doing concertos, so that's not typical. That's where I think there's also the idea that, oh, you sort of transfer Mozart's genius directly into, because it was a child genius, so, you know, you can sort of see that

feeds into that myth as well. So, well, not a myth, but, you know, that exaggeration, that sort of a preconception, that it's all, it's straightforward, it's direct, it happens every time. No, but there's something to it, but again, a sense of moderation wouldn't hurt you. Thank you for listening to this episode of Instant Genius, brought to you from the team behind BBC Science Focus. That was Dr. Dean Burnett. To learn more from Dean, check out his books, while your parents are hung up on your phone, emotional ignorance, the happy brain, and the idiot brain. If you liked what you just heard, then please do consider subscribing to Instant

Genius on your preferred podcast platform. If you'd like to see our guests and hosts in person, then please do also check out our YouTube channel at ScienceFocus. The current issue of BBC Science Focus magazine is out now. Pick up a copy wherever you buy your favourite magazines, or download us on your app store of choice. You can also find us on Apple News or online at sciencefocus.com. This podcast is sponsored by name, audio and focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name Audio believes you can have digital precision with analog warmth. Alongside French acoustic specialist vocal,

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