have brought together some of the world's best thinkers to explore the fascinating inner workings of our remarkable brain. this evening the topic covers the public policy implications of the new science of mind. our understanding of the brain's complex function as a direct impact on our fundamental notions about how we live it affects our views on justice, personal accountability and decision-making. in the state of the union address president obama cited brain research as an example of how the government should invest in the best ideas. >> we also have to invest in the best ideas. every dollar we invested to map the human genome returned 140 dollars to our economy. every dollar. today our scientists are mapping the human brain to unlock the answers to alzheimer. they're developing drugs to regenerate damaged organs. devising new materials to make batteries 10 times more powerful. now is not the time to gut

these job creating investments in science and innovation. now is the time to reach a level of research and development not seen since the height of the space race. >> rose: the obama administration is planning a decade-long effort to build a comprehensive map of the brain's activity this project will no doubt prompt further questions about how we live and govern ourselves. joining me now, walter michelle of columbia university, michael shadlen len, also of columbia university, daniel konaman of princeton university, alan alda the actor, writer and host of the upcoming pbs program, brains on trial. and once again my cohost is dr. eric kandel, a nobel laureate, a professor at columbia university and a howard hughes medical investigator. i'm pleased to have all of them here at this table. and as usual, we begin with eric kandel. >> we are going to speak about the public policy implication of the new science of mind. you know, we picked this topic almost two years ago.

and we planned to have it at the end of the second series. and we didn't realize it, but the timing couldn't be more perfect-- perfect than to have it in march of 2013. because in this short period of two years, perhaps because of the brain series, the public interest in the brain has increased enormously. so that many people, including policy experts, are beginning to see the great challenge for science in the 21st century is to understand the human mind. and this has caught the imagination of world leaders. simon perez, the president of israel at davous, at the world economic forum in january announced that he thought that the greatest problem facing humanity is the lack of understanding of the human mind. and he has initiated an award that's given every

year, a million dollars for a scientist or group of scientists who makes a major advance in brain science that has practical implications. and president obama picked up on this in his state of the union address and outlined an even bolder program, a decade-long program involving several billions of dollars coming from both public and private sources in order to get a richer understanding of the human brain. now as we've seen in all of our programs, you can't understand the brain unless you understand psychology. the two go hand-in-hand. they complement one another. and even that insight is a relatively recent one, when several of us, the more mature ones around this table, were starting out, the science of the mind cognitive psychology and the science of the brain neuroscience were separate disciplines. it was really only within the last 40 years that this

major synthesis occurred in which cog any difficult psychology and near science merged to give rise to a new biological science of mind. and this is a very ambitious science. it has three aspects to its ultimate goal. one fundamental and central is to understand ourselves better. to understand how we perceive, think and act. in addition a consequence of that is to try to get a deeper understanding and hopefully better treatments for the diseases of the brain that formed humankind, schizophrenia, depression, post traumatic stress disorder, alzheimer disease, parkinson's disease, the list goes on and on. but in addition, the new science of mind hopes to have an impact on public policy. it wants to see to what degree people's lives and policymakers thinking can be changed by insights that derive from this.

for example, what can we do to encourage the delay of gratification. what have we learn approximated about decision making that can be useful for every day life and to policymakers. and finally what is the role of the new science of mind in the courtroom. now with these topics in mind, you couldn't put together a better panel than we're fortunate to have here today. we have here two of the most extraordinary cognitive psychologists about a generation. we have here a brilliant neuroscientist interested in applies cognitive thinking to the analysis of the brain. and we have here a great student of the brain, a great communicator of science whose's recently become interested in the role of brain science in the courtroom. so we are going to discuss a number of different themes here. but one theme that cuts across all these discussions is the nature of the decision-making. so walter michele is

interested in how young children make decisions about delay of gratification. and he introduced an experiment, the marshmallow experiment which has been one of the most creative influential experiments done in cognitive psychology in the last several decades. danny canaman has won the nobel prize for his extraordinary analysis of decision-making, and his analysis of how we make judgements. and the impact of our biases on both of these processes. you're going to hear from mike shadlen len. he is carrying their approach into the brain, asking single cells how they make decisions. this is a fantastically new approach. so we can't have one without the other. you can't do meaningful biology, particularly of the human mind without having a good psychological background. what is so spectacular to me

about these experiments is that first of all they show the synthesis of cognitive psychology with neuroscience. we never have done this if there wasn't at psychology of decision-making. but it also shows you that on the level of a single nerve swell you-- cell you can see a decision making process unfold. that is remarkable. and finally, alan alda is a world famous actor and writer. he's devoted a good part of the last 20 years of his career to communicating science to the general public, and teaching others how to do this effectively. and for this he was recognized with the public service award of the national science board. he's now become interested in the role of brain science in the courtroom. and he and you will try to use the information provided here by our panelists to try to extract the public policy implications of all of this. so we're in for a fantastic program. >> rose: let me begin with

walter michele and talk about what do we know brain development that bears on public policy? >> i think for me, charlie, the part about the brain development that bears tremendously on public policy and that i think is the best news that people who care about the potential of human beings to develop well have had in a very long time is the amazing plasticity of the human brain. the plasticity of the human brain is tremendous and is particularly great in the first few years of life. and something qite miraculous happens when one watches normal human development in the period that starts with birth and goes to 5, or 6 or so years. it's a transformation that i became aware of before there was a brain science.

it's a transformation i watched in my own three daughters as they went from being what kids are at birth which is completely tied to their own sensations, completely dependent on caregivers, to becoming potentially distractible by the time they're six months old and learning to distract themselves in ways that could give relief to their own emotional distress, that is they could begin to calm themselves. to something really extraordinary that happens between two and five. and what happens between two and five is that they're able to begin to inha inhab-- inhibity impultss, dla gratification, to keep a goal in mind, to use working memory to keep going, to shift their attention in extraordinary ways. and that's really what the basis became for the study that i did that's now referred to, eric talked about it, as the marshmallow experiment.

>> a wonderful experiment. >> rose: what happened in the marshmallow experiment. >> although it's referred to as the marshmallow experiment, it actually isn't always marsh mel joes. very often it is oreo cookies or pretzel sticks. but the point is it is small rewards that are pit against each other that the child has chosen from a whole bunch. so what you are seeing in this picture is the little girl whose chosen to wait for two oreo cookies rather than one immediately. and she knows that at any time she can ring that bell, the experimenter will come back into the room, and she will, if she rings the bell, she will get the one oreo cookie but she will forego the two. on the other hand if she waits for the lady to came back by herself and doesn't ring the bell and doesn't begin nibbling on the cookie, she gets the two. that's the experiment. >> let me make sure i understand this correctly so she gets one cookie then the instruction is, that if you don't eat this cookie right

away, if you can hold on for a while, then will you have a chance to get a second cookie. >> it is even simpler. before she starts the little girl has already made a choice. she's taken what she would like to have which is cookies. and she has been told would you like the one or would you like the two of the cookies. and she's decided she would like the two. so but she understands now and what is practiced with the stuff right in front of her, both the two cookies that she gets if she wait, the one cookie that she can have immediately is that it's entirely up to her, at any time she can ring the bring me pacbell, the experimenter jumps back in the room and it's hers. so -- >> only one, not the other. >> then she gets only one, and not the two. that's the experiment. simplicity itself. i have always believed that it's important to be able to eat your methodology. >> if you like marshmallows.

>> so that is the study. now the important thing about it is it provided us with an opportunity to do experiments on how does the representation of the object of desire of the thing you want like the two cookies make it possible to do this delay thing, to make it possible for a child as young as four years old to be able to wait 15 minutes in a room that's deliberately barron, deliberately extreme, there are no distracters, she's got nothing to entertain herself with. what we found here that was surprising was that as these children at standford where these studies began, were growing up it became clear that they were different in ways that actually connected to how long they were able to wait initially. and i began to do followup work to see if we could find corelations between how long

the child waited in this situation at age four or five, and what was happening to them when they were young adolescence, when they were 12 years old, 13 years old and so on. and that was the beginning. and we found to our surprising that beginning in adolescence there were very strong corelations, much larger than we had any reason to anticipate, between second of delay time and outcomes that were very important, including at age 16 and 17 nair scores on the scholastic aptitude test, which are very important for admission to college in the united states. including things like ratings by parents and teachers of their social and cognitive competence in adolescence. and including a whole set of things that became increasingly clear when we were following them at age 32. and that included less

tendency to develop large body mass index, less tendency towards obesity, less cocaine drug use. and so on. >> walter, you make me think about public policy right away. if these tests are so predictive of future behavior, if it appears that a kid who can delay gratification for those 15 minutes turns out to get better sat scores, to do better at a job later in life, even, how would ode people in the public be reassured that such a test has at such an early age wouldn't brand the kid for life. >> particularly the kid was don't do well. >> that's what i am thinking, the kid was don't do well. do we then have kind of self-fulfilling prophecies about these kids that will sort of trail them all through their lives. what reassurance would they

have? >> so the idea of being frozen in the position on the measure is completely off. we're talking about corelations that are significant. we're not talking about a destiny for an individual. so i want to be very clear that branding would be completely missing the point, particularly since the most exciting findings about the marshmallow experiments are the ease with which it is possible to change an individual's ability to delay gratification. >> and there are ways to do that. >> there are very straightforward ways to do it that connect with how the brain works. in the experiments we've done, we've taken children who were unable to wait for more than a minute and suggested to them before we leave the room f you want to, when you want to, you can make believe that this stuff in front of you is just a picture. put a frame around it in your head. and the child understands that, knows what a picture is, knows how to put a frame

around it in the head and the moment that that happens, you walk out of the room, the child is able to wait 15 minutes. you show the child the picture of the object and you say make believe it's real, and the child rings the bell within a minute or two. >> wow. >> so these experiments which get virtually no attention in the media are really the thing that has such, i think, tremendous public policy implications because it means you can teach this. and you can teach it exactly in the earliest years of life. you can teach it in preschool. you can use the remarkable imagination, amazing imagination that kids have at that age to utilize the imagination and to do a whole variety of things that kids who are able to do this in fact, illustrate vividly and beautifully. so that's why i think the interpretation to be taken from the findings is that this is an enormously important skill. it has predictive qualities.

it has protective effects. but it is teachable, it is changeable, it is context actualized, and even individuals who are very high in delay ability are strikingly unable to delay under some circumstances, et cetera, as we know from all the fallen heroes in the headlines. >> rose: daniel, let me turn to you. you worked on a different kind of decisions than those that walter has been tucking about. so what have you learned about the likely influence on public policy? >> well, we have learned quite a bit, actually. but one of the things that we have learned is that behavior is very strongly influenced by things that should not matter. it is influenced by, for example, the way that choices are described. so for most people in a standard example, you describe a cut of meat as

20% fat, or as 80% fat-free, and people are willing to pay more for the same meat if it is described as 80% fat-free than at 20% fat. it creates a different emotional reaction, people respond to it differently. now the same kind of mechanism applies when people make very important decisions. so for example, if people are choosing whether or not to donate organs, their organs after an-- if they die in an accident, it really depends what you de-- define as the default option. so you can he did fine that unless you check this box, then you will be donating your organs. and then there is that box and they can check it. it is really very, very small effort in many cases to check that box. or alternatively, unless you choose that box, will you not donate your organs. and then you have to choose

the box if you positively don't want to donate it turns out that in europe, for example, there are about half of the countries have one default and half of the countries have another. so germany and austria which are culturally quite different have different defaults. and as i recall, you know, it's something like 15% donation in one country and about 90% in the other. now that shouldn't matter, it's an important decision. and the manipulation is trivial. and yet it matters. so we have learned that very small details make very large-- make very large difference, to an important decision that people make that has large policy implications. turns out that how you formulate the question has a very big influence. turns out in the u.k. they're applying this to influencing where the people will obey rules so it is

much more effective when you want people not to litter to tell them, people do not litter than to tell them don't litter. so by reminding people that enormous is normal s normative, other people do this, you affect their behavior tremendously. so this is one of the major items that we have learned the importance of things that shouldn't matter to decisions that do matter. >> rose: alan, jump in on this too. you and i have talked often this whole notion of cognitive psychology and biology working together. you know, is this a place for it to work together? >> you determine something's happening through cognitive psychology. and then it's up to the neuroscientists to find out where it's happening in the brain. >> that's one of the two approaches. you have neuroscientists who are taking experiments on decision-making, say, and carrying out those

experiments while imaging, you know, while collecting brain information. and you get the other way around that is you get neuroscientists finding that a certain function is being done, say in two different ways or in two different parts of the brain. and that's just psych logical high pot ceases in ways that cognitive psychologists would not have gotten too. >> rose: how do we think about free will and individual responsible. >> it's a big topic and begins in antiquity but thankfully in neuroscience it begins about 30 years ago in experiments by bench lynn la bet. maybe we could have the video, labet did a very simple experiment. he had his subjects sit. he told them to relax, look at a clock. and whenever they were ready, they should move their hand. that's it. now he asked the subjects to note the time on the clock at the time-- when they first felt this urge to move, okay. and all the while he's

measuring activity from the brain, that's you what see in the monitor there, it's called a redness potential, it's record like an eeg from the head. and labet discovered a couple things. he found that the people not surprisingly reported that their urge to move occurred before they actually moved. and he also confirmed the existence of this readiness potential, this activity in the brain that precedes the movement. no big surprise there but the surprising finding was that the same potential, the same readiness potential occurred about a second before the subject had any subjective awareness of their own intention to move. and some people find that very disturbing. they find it disturbing because it seems to imply to at least to some, that the will to move was just an illusion. it's just this thing caused by the brain. i have to say that for my point of view i would be more disturbed if the will to move wasn't caused by the brain. so-- to a neuroscientists,

neuroscientists aren't at all surprised that there is activity in the brain that would precede a movement. and i don't think we should be terribly surprised that there is activity in the brain that precedes an idea to move. and the same kind of logic applies to responsibility for a decision. the brain cause us to make decisions. but that doesn't mean we're not responsible for them. i mean the brain causes us to do everything, after all. for example when an artist makes something novell and wonderful, okay, it was the brain of the artist that made her do it. and you know, when we explain the machinery of the brain, we don't explain away creativity. and we don't explain away choice, volumician and spoblingted responsibility. i think we have to be much more refined in our thinking. now what the labet experiment does that is really wonderful, really as i see it his legacy is he got the ball rolling. and he said look, you can measure events in the brain that are responsible for

mental states like volition, like the urge to move. and that's interesting. and in the last 20 years we've seen this really this enormous explosion of what dannie was referring to as decision neuroscience. and it's now routine in many labs around the world to record activity from even single neurons in the brain, single nerve cells that are involved in deliberation and planning and probable election reasoning and even assigning confidence to decisions. and i think that those, the insights from those kinds of experiments are providing kind of a new angle on some of the building blocks on cognitive science what we were discussion a moment ago. and i think they bear, they have some bearing on responsibility. the kinds of things that allen is thinking about in courts of law and in society. and let me try to explain what i mean by that. i will just give you one example of a finding from neuroscience. we're beginning to understand how the brain trades off the speed of a decision against the accuracy. so for example, eric and i

might be observing the same fact but we might reach different decisions because i might be pretty quick. and eric might be slower and more deliberative. eric might make the better decision. i think that is probably correct. >> go on. >> the idea is that we're understanding the speed accuracy trade-off as a level of neuromechanism, okay. but it's bearing on what makes one decision maker different than other. one may be more impulsive. or more methodical, or perhaps paralyzed by indecisiveness. and it's at the level that this is at the level of neuromechanism that we can begin to get a handle on that. now what does that mean? it doesn't mean that-- that we can say with the neurons what someone is going to doment it doesn't mean that we can say, using neurophysiology whether someone has lied or told the truth. we can't tell whether someone's guilty or innocent and we can't tell society how they should balance

punishment or punitive methods versus rehabilitative methods in criminal justice system. but what i think we can do especially in the 1e9ing of disease is have some insight to some mitigate-- mitigating insight about the degree of culpability, say. or maybe be able to form proct no cease about the possibility of rehabilitation or predict the probability of recidivism. and this is the role as i see it of neuroscience, of decision-making in both in society and in the courts. >> let me move this to the courtroom. well, i'm issueding a program for pbs called brains on trial where i spoke with a couple of dozen neuroscientists and a number of people in the justice system. i came away from that with two very strong impressions. one was that there is an amazing amount of, for

someone on the outside of your science, it's an amazing amount of new knowledge about the brain that is exciting a lot of interest in the justice system, attorneys are very interested in the fact that now they realize now you can look into a brain while it's recognizing a face, while it's remembering a place, while it's experimenting an emotion. and so some people may be saying to themselves well, why don't we drag this guy in, put him in a machine and see if he really feels remorse or is he just saying he feels remorse. and there are at least two companies who claim to be able to use an mri machine like a lie detector and that i believe they're getting alot of pushback from scientists on that claim. but the brain scientists, brain scientists already begun to come into the courtroom and two or three

supreme court decisions, one, at least one of which references brain science, am i right about that. >> yeah. >> is this being accepted by the courtroom. is it being accepted by participants in the judicial process or do they say i'm just so sure and maybe show me more. >> i think there are a number of judges who are very reluctant to bring in. and scientists that i've talked to are very reluctant. >> very reluctant. certainly premature. >> prematurely because they don't think the evidence is there to make the assumptions are you making. >> is there a problem in the fact that most of these studies are not studies of individual brains so that you could say here's -- >> it's an average of many -- >> so how do you apply that to this one person. >> daniel you were saying. >> well, i mean i think that everybody will agree that it's premature. many scientists will agree that it's premature.

but if you had to predict whether it will become-- common plates in a few decades, it will be. >> no question. >> this right now is-- it's too early but it's happening. it's going to happen. >> because it's technical, because you can show pictures, you have this big expensive machinery. >> it looks more reliable than it may be. so there is a certain amount of self-hype that people are introducing. i don't mean scientists. >> don't give enough credit to the insight of human being's psychology that we're pretty good at telling reliability of testimony, just on the basis of listening to it. and at the moment that's sophistication that we bring to bear on testimony is probably significantly greater than the information that we can get out of imaging. >> there is also a matter of the level of analysis. so the mri is a very s a crude measure. a measure of whole brain

area, at a time at a crude spatial scale, at a crude temp oral scale. and you know, the underlying mechanisms turn out to be far more diverse, not that we know really that much about these mechanisms at this point. we're in our infancy but i suspect that, i mean i agree with danny that we don't know where we'll be 10 years from now and any information that we have that helps us make decisions, that's fantastic. if i had to pet on-- bet on t i will bet it won't be mries in the courtroom. it will be more refined. >> what does the delay gratification tell us. >> in the brain. >> i think it's been useful to conceptualize essentially two brain systems that are continuously interactingment but as one goes up, the other one goes down, is a reasonable way to think about that interaction. so it's more of a metaphor than an accurate description of pieces of what goes on in the brain. but it's a useful metaphor for thinking about things that do have a reality in

the brain. and i think of it as involving two systems, one of which we can refer to as a hot system, an emotional system, a reflective system, an automatic system, a system that is much closer to what eric was talking about with the unconscious. it's automatic and it's essentially the natural default. it's what has the child ring the bell or take the cookie, rather than activate the cool system. so what's the cool system. the cool system is cognitive, it's slower, it's more complex. it's reflective rather than re-- reflexive, the hot system is probably amygdala and venereal-- in the brain so it is different areas t has to do with fear and the reward system. the cool system is much more prefrontal cortex. the hot system is there from birth. the hot system is tremendously accentuated by stress so it

goes up exactly when we need it most. in some ways it's good to have it go up from an evolutionary point of view, it meant that you had a fight or flight response immediately which was very good when we were in jungle conditions. it's less good when we are in a traffic jam. >> that brings me to daniel, talk about fast and slow system. >> well, it's-- you know, people from time immemorial have divided the mind into two systems. and walter has the hot and cold and i have a distinction between fast and slow, system one, system two. they are-- well, because they are highly correlated but they are not identical. the distinction for me, the proto typical difference would be between what happens in your mind when i say 2 plus 2, and something happens to your mind immediately. or when i say 17 times 24, which again you probably could compute but it would take you time it would demand effort.

your pup wile dilate amount of lot of different things would happen. the system one and system two are clearly system two is closer to what walter calls the cold system-- cool, not cold. and system one as i can see includes the hot system but it's more than that. because it also includes essentially all the automatic functions of memory. >> yeah. >> and so that's what brings 2 plus 2 to mind. and system two includes as i can see everything that demands effort, mental effort and control. and part of it is inhibition of impulses and part of it is computational. all of these demand effort. >> specific examples. >> well, system two would be involved whenever you have to make a choice.

>> system two to go back to charlie's question is involved when are you trying to wait for two cookies. >> absolutely. >> and system two reknow, for example, that when people are cognitively bus eye, when you ask people to keep seven digits in their head while doing other things, so their system 2 is occupied, their ability to inhibity impulses is-- they use more-- while they are keeping that material in their head. and in many other ways you can see that their self-control is impaired. so there is a corelation. it's very close. between the resources that are needed for self-control and the resources that are needed for computation. >> rose: so what do we learn from this in terms of our behavior, there terms of how we go about thinking and making decisions that are beyond that of a marshmallow? >> well, we learn that there are conditions under which we can trust our intuition.

and conditions under which we had better not trust our intuition. and more importantly, we learn about cases in which can committee trust the intuitions of other people and in which we can be skeptical. >> rose: how do we learn that? >> well what we have learned is that self-confidence or confidence in one's intuition, this is something that people have when it's justified, when they have a skill am but you can also have a great deal of confidence and intuitions that are not based on skill. they're just based on events that happen in the mind, which are not reality. and that overconfidence is something that we can recognize and you know there are professions which are to some extent, i think, based on an illusion of skill. and that is true, people tend to guess what the stock market will do. >> right. >> they can't do it if it

could be done t would be done. it's not doable. and yet people have the feeling that they can do it. and that is an interesting psychological phenomenon. where does that confidence come from when it doesn't come from reality. >> what did we learn from the cellular level, michael. >> well, i'm listening to the gentlemen talk about levels of understanding at a very broad level and extremely important one. and this this point one that has a greater relevance to our behavior than anything we can tell you at a yell lar level well that said i think this refined understanding of the brain, the brain's opinion ree to make decisions, i think, is going to be very important. i mentioned this earlier but now if you don't mind i will show you an example. simple animals function primarily with reflexes. they channel sensation, directly to the motor system. but higher organismsing especially primates have he involved large areas of the brain that we call you will associations, as they

interpose between the sense other areas like the visual cortex in the back of the brain and the motor cortex. and we can study neurons in these regions that give rise to decision, they parallel the processes that walter and danny were describing. now neurons as i'm sure your viewers have learned from your previous shows, they communicate with each other with little electrical events, we call them spikes or action potentials. and when you play these little action potential or voltage blips to a loudspeaker we can hear them, making little click sounds. so when a neuron is excited it goes -- and when it is not it just goes tick tick tick or is silent. >> rose: you can hear this. >> you can hear this i play new a moment what it sounds like. but what characterizes neurons in say the visual cortex, the sensoree cortex and motor cortex is that their responses are brief. they go-- brrr, why, because they have to cope up with a changing world and they have to control body musculature in realtime. higher brain function invite

invites-- an escape, really, a freedom from that media see. so it characterizes the association cortex, is that those responses are prolonged. these neurons go brrrrrrr and fill the gap of time so i would like to show you probably the simplest task that could be imagined, really, to study memory and fill the gap of time. so this is a simple-- simple working memory testament i will ask you, charmie t to look at the white dot. >> rose: yeah. >> and then you just stare in the middle of screen and wait for a red spot to appear somewhere and remember its location. so there it is. >> you continue to look at that white dot. and little while later, just look at the-- remembered position of the red spot. so you should have looked where this arrow is pointing. a that is about as simple a task as you can imagine. soho is that going to work. some part of the brain has to hold on to that information about space while you were waiting. okay, so it unit is out this

is an easy enough task to have an an pal do. so i will show you now, play for you now, the sounds of a neuron, of course neurons don't make sounds, these are just electrical pulses they use to communicate while a monkey is doing this tax. i would like to reassure you that the monkey is completely comfortable while he is doing this task. let's look at the video again. the monkey will you see his eye position in yellow and let's see if we can hear the neuron spiking away. so-- there is that red spot, and the monkey made his eye movement to its remembered location, and you see this activity that separates this pulse of light, that red spot before the monkey actually made his eye movement, that is what we refer to as persistent nearal activity that elevated spiking continuation should have sounded bbbrrrr going across in time. and what it does is connects the gap in time between something happening in the world and something that the monkey had to do about it.

and if you think about it, this element which is a very common feature of the association cortex is the key to connecting the path to our presented and the present to our immediate future. even over these short time scales of a few seconds, just imagine what life would be like if you couldn't do that. you would be hopelessly confused. so i think this is an observation that has tremendous insight into many cognitive functions and in disease, sort of you might say it keeps us from being confused. that normal function of the brain. well, it turns out it also holds the key to understanding decisions. so now what we will do is i'm going to tell you about another task that is a lot more complicated. it's a bit like predicting the weather. what we're going to do. we watch the video, is we're going to ask a monkey to make a decision kind of like deciding between weather it will be sunny tomorrow or rainy. but here he has to just choose between green and red. and he's going to make the decision about which one is more likely to give him a reward based on these shapes that we show the monkey. so es -- >> he's learned these shapes.

he's learned that five of those shapes support reward, those were the shapes you saw on the left and one of them was very strong, reliable, one was much less, and everything in between. then you saw five shapes on the right side, and those support reward for the red. so these are different kinds of cues, like the barometer reading and the clouds and you get your-- you've got to decide. you might have conflicting evidence but you've got to make a decision. okay. so we asked the monkey to do this kind a test but let's again, let's have eric, you will do this first. so -- >> i'm not sure i'm up to it but go ahead. so let's say you see a bunch of these shapes so there is a pacman and you learned that that provides weak evidence for green. there is the pentagon that supports red. now you're kind of neutral. okay there is this unwhich supplies evidence for red, followed by this inverted triangle. more evidence for red. so eric what are you going to do. >> straight. >> okay. is so that -- >> i'm ready for the israeli army now. >> and he's very confident about it too.

so we can have a monkey do this task, okay. and because they're trained and they've learned these shapes, okay. they've had a lot of practice. and what we will do is show that same trial but now in realtime and will you see the monkey's eye position as we did before in yellow. he will stare at the fixation point and see those shapes come on and will you hear this neuron. the thing you need to know about this neuron is that we already know that this is a neuron that is excited bid evidence for red so it should respond more as the evidence builds up for red, okay. let's see whether the monkey is as clever aes rick and weighs the probabilities correctly. so what you can see leer si anybodially that first pacman supported green and the firing rate, these spikes were little gaps of space between them, okay. there was silences. so there weren't very t wasn't a very high rate. gradually you saw those gaps give way so that it was just, the screen was just paint.

because that neuron was just screaming away, i'm seeing lots of evidence for red. you saw that the monkey chooses the red target. i will show you one more trial, kind of interesting. this is the same neuron and this time the shapes will be, the first shape now is the pentagon. if you remember that is the weak evidence for red. and that's followed by a triangle, weak evidence for green, there's our pacman. more evidence for green. and then yet more evidence for green. okay, so this is the opposite kind of a trial. and so the weight of evidence, of course. in the end supports green. let's listen the same neuron. now remember this neuron, this neuron is, is excited by evidence for red. so it ought to be suppressed by evidence for green. lo and behold that's what happens. the monkey chooses the green and you saw initially that first shape supported red there was an elevated spike discharge. and then gradually it gave away to basically silence. >> so presumably there were

neurons that respond the opposite way. >> absolutely. >> and they would be, they would have been increasing their discharge. >> so green and slowing down to red. >> what amazes me about this, it is really a beautiful thing to hear the clicking like the liking of an abicus while the cell is calculating probabilities. and this is a naive question so excuse me. but it's so interesting that in your work, danny, we're constantly being fooled about probabilities. and in the history of our species the whole notion of probabilities came in way late. and yet here's the machine key and presumably our single neuron, just to pick one of the many at work here, but here's a single neuron figuring the probabilitiesment how come when you get to the level of the whole brain it's no damn good at figuring probabilities with because it is figuring out very different kinds of --

>> in one situation, you know, the relatively simple stimuli, they are related to each other in highly predict-- predictable ways and you have computation which involves an enormous number of cells converging on that single neuron which in effect weighs the difference between the evidence for red and the evidence for green and responds accordingly. >> when we are speaking of mistakes that people make in problemmistic reasoning, we are using the language system, we are talk approximating about probabilities. we have mental representations of global complicated events. completely different story. and you don't do that, by success isive reinforcement of responses which is a way that michael gets, -- know. >> this is a beautiful exam pe of science in action am when you take a complicated problem from a biological point of view, you want to study its most elementary

representation that is meaningful. this is what michael is doing. there is no reason why you can't make this more complicated. and add other dimensions to begin to get to the level that danny is talking about. >> and it could be a call tatively different. >> it actually is not the same mechanism. >> danny spent a lot of time talking about this fast system, system one or cool and walter's terms. and as you point out in your book, system one is actually pretty clever, okay. it's responsible for a lot of interesting errors. but actually it gets us through life. and we are pretty rational. that's what we are seeing here. is that our brain, our fundamentally rational, we do get through life. i'm talking about fon diseased brains, okay. and so that is what is happening here. we're seeing the basic machinery of machining at the level of a single cell. and it's not really a contradiction to say that there are ways in which i think that same machinery might give rise to its decisions we make to event

narrative, invent stories about things. make a lot of sense in our world. and now at the risk of making some logical errors,. >> i often wonder, i'm really curious to know what your response to this would be. when you reduce the problem to something very simple like being aware of the shapes showing up and which direction to look in, the neuron has one task. one neuron, one task. when su have a global problem what what stock to pick or how to judge somebody's future performance based on what you are seeing at the moment, is it possible that you have competing parts of the brain, each looking for dominance and one may choose a path that is totally against the probabilities but if suppressed by other areas would make a more rational choice? >> what really happens is, you know, you would have

that at the level of the single neuron when the evidence is ambiguous. and so there going to be some randomness in the behavior of the neuron and behavior of the monkey. now 9 same thing happens globally when the information is actually not there. a decision is still made. so you must make a decision. and the system is really designed to make decisions even under conditions of uncertainty. because waiting is biologically very costly. >> and it's a decision. >> i think that allen it's a very good point here. first of all he is recording from a single cell but this does not happen at the level of the single cell. he is sampling it and using a cell as an example. i see no reason to believe that if one increasing the complex ability of the context, that cell can be diseased. you'll see a reflection on the cellular level of the kinds of things you're talking about.

they've got to be -- >> no, but i don't-- i think, michael, michael, will correct me, but i don't think we should think of this sing el cell. fl there are millions of cells behind that single cell. >> of course, of course. but you can sample a cell that is closer to the output that is going to carry that information. that will reflect the decision. >> i have to close this down here in just a moment but go ahead. >> i was just going to say that the critical thing is that the operations that the cell is doing are not just about what the answer is going to be or just what the information on the screen was that gives rise to it. it's those steps along the way that are important. and as allen points out there might be competing concerns but different neurons might weigh differently the prior knowledge of what the probabilities of the outcomes are going to be. the amount of costs associated with time as you point out or emotional ackers or social costs. and those are the kinds of things that make, again, back to the original question you asked me about soblt, those are the kinds

of things that make decision makers different, even thoughthey're based on the same basic neuron machinery. >> on that point i have to thank alan alda, my friend, thank you. michael shadlen len from columbia howard hughes medical investigator, walter michele, daniel konaman from princeton, nobel laureate and my colleague eric kandel who has been involved now two seasons of trying to understand the brain and appreciating the remarkable contributions that people are making. nd as they would be the first to tell us, just beginning to understand this remarkable thing. so i close this session, this brain episode two series with eric and the question, what do you hope our audience carries away from this series of conversations at the table about the brain and also about diseases of the brain and what they teach us?

>> i hope they carry away the idea that every mental process is a brain process. there's nothing mystical out there. that we are beginning to get an understanding of how the brain functions. and we have a rich psychology that provides a background of what we teed to explain and the psychology will grow. but that brain signs which offer tremendous promise for understanding how we function, both when we function well and in disease is at the very beginning of really maturing as a discipline. but we now are in a position where there are tools available that we didn't have 10, 1 years ago. these tools are getting better. we'll be able to record not only from single cells but from whole populations of cells simultaneously in different areas of the brain at the same time, imaging techniques will improve and so we'll have much better resolution. we'll be able to come back here 10, 20 years from now

and answer all of these questions from the satisfaction of the two gentlemen on my right. more over and this is equally important, we are in a terrific state in terms of curing major diseases of the brain. we have very little insight into schizophrenia, we have very little insight into depression, although that is getting to be stronger. by working out the neurocircuitry of these diseases we will for the first time have biological markers that allow us to track progress with the therapeutic approach way new drug and understand the nature of the disease and how to treat it. so this is the way ahead for really many. problems that affect individuals and therefore soes. >> rose: i'm happy you said that because obviously we have not exhausted the subject. so there are many programs. and we will be thinking about that, if you have ideas for what you would like to see us explore within the context of the brain as we mentioned earlier, the president himself has marked this as an important development for us, extraordinary things are

happening at columbia. allen is doing interest ing this-- things on public television. everybody who has sat at this table including tonight is engaged in an ongoing curiosity, an ongoing experiment, an ongoing search for understanding. and the more that we do understand i think the more we will understand what it means to be human. so thank you for joining us for this series, for last year's series and we look forward to seeing you again for the next series, good -- night captioning sponsored by rose communications captioned by media access group at wgbh access.wgbh.org

ramping up, employers add 236,000 jobs in february, pushing unemployment to a four-year low and vaulting the dow to another all-time high. the fed's next move? bill gross, manager of the world's biggest bond fund weighs in. and the american recovery, four challenges that could unleash prosperity for imperil. good evening, everyone and welcome to our public television viewers. suzie today another historic day all about jobs. >> it was a welcome surprise in the jobs numbers and the unemployment rate standing at 7.7% tonight the lowest in more than four years. american businesses added 236,000 new jobs in february, cutting across all sectors of the economy, and that burst in hiring inspired investors. stocks were up again today

making this a week of records for the dow jones industrial average. the dow rose 6 points closing at 14,397, another record high. the nasdaq added 12, the s&p edged up 7 points and this is the tenth straight friday of the year that the major market averages were up. so where are the new jobs? what sectors are still seeing weakness and what is the role of the federal reserve in the labor market? steve liesman has our report. >> reporter: a solid jobs report renewing hopes that the u.s. economy could be chugging along just fast enough to put americans back to work. economists are encouraged by this report but they're concerned that the strength may not last. that's why goldman sachs economist says the federal reserve is unlikely to change its easing monetary policy from this report alone. >> the question i think is more how many times months do you have to see to be convinced that is the underlying