Rebecca Saxe: The Brain vs. The Mind

[Applause] and joining us now in studio Rebecca Saxe associate professor of cognitive neuroscience and principal investigator at the sax lab at MIT hello nice to meet you nice to meet you I want to start with talking about the difference between neuroscience and cognitive neuroscience neuroscience is the study of the brains functions but cognitive neuroscience also takes into account the mind so lay it out for me what's the difference between the brain and the mind oh wow well start somewhere a little easier with neuroscience so neuroscience is a field that has a hundred year history of trying to study the functions of the brain and for a long time the easiest way to do that was to study the brains of animals to study mice and cats and monkeys and what was really hard was to study the things about the human mind and brain that are different from anything any other animal could do so we could study the things about our brains that are like other brains how we see how we move our hands how we navigate around the world well we couldn't study was the things that human brains do that no other brain can do like language or moral reasoning and those things were basically philosophy until about 15 years ago with the beginning of cognitive neuroscience where basically what became possible is studying the functions of healthy human brains and that let us really let then let us study as neuroscientists the things about the mind that we most wanted to understand you mentioned studying other animals how much of what we know about the human brain comes from the study of other animals brings on most topics almost everything we know so that what we know about vision how you get from your eyes to seeing the world around you almost everything we know about how the brain does vision comes from other animals but think about something like language how you understand a sentence since no other animal does anything like human language or communication on the scales that people do or teaching right no other animals teach the way we teach in an organized fashion to strangers for pleasure and so anything we know about how the brain does that we've been learning just recently by studying human brains directly you talk about humans being natural born it teachers how are we like that well how is the $64,000 but probably more than that right no absolutely that would be a career in a house so what we do know is that people set out to teach and help other people to understand things and in other animals you get very rare occasional teaching but what you get in humans is just teaching of everything to everyone all the time the idea that you would build an institution like a school or a university where somebody would go to spend their time teaching strangers children is definitely a uniquely human idea okay so if we have all that on the table for the human mind what's the distinction with the brain there well in a sense we don't know right because the functions of the mind where we understand how they relate to the brain are the ones that we've been able to study for so long so we know quite a lot about how the cognitive functions of vision how what what the world looks like to us the experience of seeing like seeing color or depth we know quite a lot about how that experience relates to brain function what we know much less about is how would a pattern of electrical activity in a brain cell relate to thinking about morality and so they must be related right any time you have a thought whatever it's about about a legal case about a problem you've had with a neighbor about how to teach your child how to walk every thought you ever have is happening in your brain and so there's an answer to the question what pattern of activity across brain cells is it for every thought you've ever thought but we don't know the answer for almost any of them that's your job to forget so that's my job I want to talk about cognitive neuroscience and how it can tell us how we make choices so one interesting discovery about the human brains that you've said is how we generate a number of choices in any given scenario before selecting the appropriate one explain how that works well so one of the ideas that you're maybe talking about is that something modern neuroscience revealed you may think when there's a bunch of objects in front of you you only ever generate the action that you want to do so if you're thinking about writing yeah you're thinking about writing on this piece of paper or drinking the idea will only come into your mind when it suits you when it fits your goals what neuroscience has shown is instead your brain is constantly creating all of the possible actions that you could possibly do all the ones you see me do all the ones objects around you would let you do so you see a pen and a cup of water and your brain has already created the idea of how you would reach for the pen to write how you would reach for the water to drink and then it's suppressing those ideas so it's made them all ready to go and then it's holding them down and it's a different part of your brain it's a part of your frontal lobe that holds down all the things that you don't want to do and we know this because certain kinds of damage to the frontal lobe that you could get with very particular kinds of stroke removes that suppression or inhibition and then you get these amazing behaviors where just putting a pen in front of you and you'll create the action to pick it up and right even if you didn't intend to do so this is a behavioral response does this the same idea apply to an emotional response that's very interesting it seems to at least in the case of mirroring so it does seem that if you see me make an emotional expression of any kind some part of your brain is making the same emotional facial expression so you smile I smile I smile some part of your brain that's computing a smile you don't have to do it but some part of your brain is making that smile ready to go there we go okay philosophers and psychologists attempt to figure out how human beings deal with moral dilemmas how do you approach it as a neuroscientist right well so this gets back to exactly what we've been saying is that from a philosophers point of view you want to think of what are the reasons that you would make a moral judgment from a neuroscientist point of view you want to know well what are the parts of the brain that are doing those those judgments which are the different pieces of the judgment and how does your brain construct them so the particular kind of thing that I've worked on is one piece of the puzzle you know moral judgment that's a very big complicated space and I've worked on one part but one part that I think is very important and very specific to human moral judgment which is our ability to forgive other people for accidents right so that's not the only thing we do when we make more but part of how you know that it's a moral judgment that you're making is that it doesn't just depend on what happened it's not just you hurt me and I'm mad I consider did you mean to hurt me did you know you would hurt me and it's that ability to take into consideration what the other person intended and that we've tried to study yeah one of the examples in your research that I found interesting was this one life of versus one life was sort of explains what you're just saying so tell us the example so the example that you're talking about is actually about a different issue which is a one life versus five lives but it gets to a similar bigger picture which is at a first blush you might think how do we decide if something's morally okay or not well we just consider how much harm was done how many people were hurt and if that were true then anytime you had a choice between one life and five lives you'd always choose the one life but there are these famous examples there are thought problems that come from philosophy and they're called trolley problems that would that's the kind of group of them and because the standard example involves a train so in the standard example you say there's a train running them down the track it's completely out of control its brakes are broken and if it keeps running down the track it's gonna kill five people who are stuck on that track but you have a choice if you pull a lever you'll switch the train onto the side track and on the side track it will run down the side track the five people will be saved but there's one person standing on the side track and that one person will die and the question is usually you're a passerby you have to make a split section second decision is it okay to pull the lever switch the Train save the five lives and at the expense of one life almost everybody says yes that's okay but here's where it gets tricky now I give you the exact same situation there's a train it's running out of control down a track it's gonna hit and kill five people at the end of the track you're a passerby and you have to make a split-second decision can you push the guy sounding next to you down onto the track if you do that the train will run into the guy and it will slow down enough that it won't kill the five people is it okay to do that what do you think probably not probably and that example tells you that it's not just the trade-off between one life and five lives that were considering when we make moral judgments and what does that I mean it wouldn't even I wouldn't make that decision but you're you're saying that this is sort of universally that everyone would come to the same conclusion that I just said I those two cases that I just gave you most people agree so most people say it's okay to pull the lever but it's not okay to push the man and what people disagree about philosophers as well as regular people like us is what makes the difference why is it okay to pull the lever in one case but not to push the man and what's happening in our brain that allows us to make this moral decision exactly and so one possibility is that you're considering the thoughts of the person doing the action and what it is that they intended so a suggestion that some philosophers have made is the reason that it's okay to pull the lever allowing the man to be killed is that you didn't intend to kill that man you knew he would get killed but you didn't actually intend to kill him whereas in the case where you pushed him you actually intended for the train to hit him because that was the only way to prevent it from killing that the other five people okay we've talked a little bit about what's happening in our brain when we're interacting with others and the tool that you commonly used to observe this is something that I understand that's called neuro imaging mm-hmm what exactly is neuro imaging and how does it work yeah so neuro mijung is a an umbrella term for a bunch of different techniques and what all of them have in common is the ability to see inside your skull without cutting a hole in it okay so totally for the best well we're not usually allowed to cut holes in the brains of the undergraduate and so if we want to study how human brains work we have to be able to do it from outside the skull and neural imaging is what we call a bunch of different ways of taking pictures of the activity of the brain when we can do it by taking pictures through the skull you can do that in a bunch of different ways and probably the two most common ways one of them is using an MRI and so that's the same kind of MRI magnetic resonance imaging that many people will have experienced at a hospital for medical serums we can use that same tool to take again the same kind of picture of brain anatomy but then what we do is lay on top of that basically a movie of blood flow in your brain so your brain cells like your muscle cells when they're working really hard they use up oxygen and blood brings new oxygen to the cells that need it the cells that have used up their local supply and it turns out that we can use an MRI machine to watch that blood flow going through your brain and that gives us a sense of where was activity happening where has the oxygen been used the other tool is called EEG or a bar an electroencephalogram what that is is a tool for measuring electrical activity because actually your brain is an electrical machine one brain cell to another brain cell they communicate with electricity and we can basically sense the edges the periphery of that activity by putting electrical sensors on your skull okay explain to me a little further because there's the layperson what I take away from this is that you can see that activity is happening my brain so something is happening but what how do you read into that like you're just seeing blood flow what do you how do you read into that path that's a great question and that's where it that's what makes it fun to be a scientist so that's where we have to design experiments so of course there's always blood flowing around in your brain you want it to be that way all the time or else bits of your brain would die so you've got blood flowing all through your brain all the time but if you're doing something at one particular moment some parts of your brain will be working harder than others like imagine the difference between doing squats and doing curls right at some points you're using your quads more and at some point it's your biceps more so it's kind of the same in your brain as you switch from daydreaming to focusing hard on a math problem to squinting to see your friend in the distance different parts of your brain are working hard and so what we do is we say okay for example I'm interested in where in your brain is the activity really going when you're making a moral judgment so how would I find that out well I give you a moral dilemma right now and then I give you a break or I give you a chance to do a math problem or a chance to think about a spatial navigation problem how would you get home from here and now I give you another moral judgment problem and now another math problem so now I knew no over the course of an hour exactly when where you do making moral judgments and when were you doing other things and then what I look for is where are the bits of your brain where the oxygen consumption really got going every time I asked you to do a moral judgment problem and not at all the other times and that's what I'm looking for break it down for me in terms of understanding so you've now mapped this scientifically this part of my brain is active and this is how I make a moral judgment what can we extrapolate from there more broadly though well there's a bunch of different ways that we can go with this kind of knowledge and of course I've only given you the surface effort right not getting into the nitty-gritty and but basically this knowledge has sort of to two avenues so one thing we can do with this knowledge is understand our own minds better right by watching exactly how our brains compute the things that they do we can know how we think and predict our own thoughts and judgments better and it gives us I think of neuroscience one of the things it is as a form of self-knowledge its scientific self-knowledge the way that scientific physics is scientific knowledge of the world around us and I think it's extremely desperately necessary that we understand ourselves as human beings better and better and better because the problems of society around us are problems of organizing people of getting people to work together to do the things we want them to do and we'll only be able to do that by understanding people better the other thing is clinical and so that's the thing most people think about is these are parts of the brain that can go wrong under certain kinds of diseases so these parts of the brain can be affected by stroke they can be affected by developmental diseases like autism and to have a sense both of what's going wrong and how to fix it we need to know how it works typically reputable science journal stress that we need to to be cautious wary maybe when interpreting the results of neuroimaging and they suggest that the processor may be subjective do you agree with that it kind of depends what you mean by that question so neuroimaging like any kind of side can be done better and it can be done worse and when you're inside the discipline if you went to a scientific conference and you listened to scientific scientists talk to each other they would be arguing from the beginning of the day to the end of the day what's the answer and what does it mean and so if you you certainly shouldn't get the impression that every new result is as rock solid at you know as the as evolution right I mean this is cutting-edge science and we're inventing it as we go along on the other hand and it's not subjective in the sense that you can just make it up right there are experiments that you know there are procedures there are statistical rules so I would say caution but not suspicion I think you it's true that you want to look for places where there's been a little time there's been chance for consensus to emerge where more than one scientist or more than one lab group has been able to come to the same answer in those cases I think you can have a lot of confidence the field that you're in the cognitive neuroscience brand new how old when did we start really getting into this well the kind of neuroimaging tool that I use MRI has been mostly available since the mid 90s and how far have we come in this in that field since then well that's really hard to say because in order to say we've come ten percent of the way I'd have to know where we were gonna be when we got a hundred or some of the way but I would say on the one hand we've come astonishingly far the brain region that I studied the one that lets you think about other people's thoughts and we didn't know it existed even 15 years ago and now we've had 15 years of data that tells us where it is and a whole bunch of the things we wanted to know about how it works on the other hand I would say most of the fundamental questions about how the human brain works remain unanswered and that's part of what makes it so exciting to be a young scientist in this field why is it now why you said he said MRIs really 90s is it a product of technology that we've now gotten into this field or is it because in society we're now interested in these questions are more interested no I think people have always desperately wanted to understand their own minds and understood that science would be a way to do it and the science that I do inherit a lot of ideas techniques hypotheses from all of the science that came before that didn't have an a tool like an MRI but definitely the MRI has opened up a whole new world I mean this field when I started in my little area which was around 2000 so around 12 years ago at that time there had been four papers published on the topic that I study and now it's well over a thousand so in that little bit of time and just the invention of this tool the MRI has vastly expanded our possibilities you told me before we went on air that you're from Toronto I am and you're quite young you're quite but you're a leader in this field did you go to school here I did yeah born and raised and then you went off into other great places to further your degree I did I got an undergraduate degree in England and then to the u.s. to study and I have to ask this cuz when we talk about science especially burgeoning fields of science we usually see it as a male-dominated field are you a lone wolf a woman amongst to feel the men in this area uh definitely not I would say my field was pretty balanced there's about half and half but I was very lucky to have among my many fabulous mentors and colleagues and both my mentor and undergraduate and my mentor and graduate school were phenomenal female scientists and I think that has been a great boon to my career you now have your own lab is called the sax lab it didn't offer you that's pretty cool Thanks what is it what how many people work for you in your lab now about 15 to 20 depending on how you count I count one two three is there another way to count well some people are full-time some people come and go we have undergraduate research assistants who join us for a semester to learn a little and go on to experience other things and what do you what do you folks currently working on now oh all kinds of things that's part of what's so great so um you know this central topic that I study how people think about other people and lends itself to going in many different directions so I've got some people in my lab studying autism for example so thinking about other people is a really a really hard challenge for kids growing up with autism and one of the things we want to know is can we figure out in the brain what's going on in kids who have autism because only when we know that we'll be able to help so that's one kind of problem another question we're interested in is when kids brains are developing we want to know how much of the structure of their brain basically which part gets assigned to which job how much of that comes from the genes and how much comes from the experience they have of the world around them so one way to test that idea is to study kids who are having a different experience of the world so right now we're studying blind and deaf kids to look at how their brains organize functions when they get different access different experience of the world that's a second problem and then the third problem often a totally different tangent when do we use ideas about other people's minds well one context is in a fight or an argument right when you disagree with somebody either about something small or in a fundamental way in an ethnic or political conflict part of what's always at stake is the other person's ideas and their intentions are they in good faith did they mean that why do they have that ideology that's always one of the things you're thinking about and so one of the things we're doing is studying what brain regions get involved when people on opposite sides of a political or ethnic conflict are thinking about each other wow that's fascinating okay we're gonna enter the sex love as it has it is tomorrow when we talk about the kind of research in more detail but what you lobstering thanks a lot for talking with me today thanks so much for having me support Ontario's public television donate at t v-- org

Channel: The Agenda | TVO Today

Views: 72,941

Keywords: brain, neuroscience, health and research, psychology

Id: vLcdKXE4R0s

Length: 21min 25sec (1285 seconds)

Published: Tue Jul 24 2012