Making Sense - Sam Harris - #322 — Predicting Reality

00:00:00.000 welcome to the making sense podcast this is sam harris just a note to say that if you're hearing

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00:00:38.840 well trump has finally been indicted for willfully mishandling classified documents

00:00:52.680 the details are fairly amazing once again we see the evidence that the man has never been playing

00:00:59.860 4d chess he just so recklessly and pointlessly violates norms and compromises the integrity

00:01:07.980 of everyone around him and he's been so immunized from political consequences by having bent the

00:01:14.340 republican party into a personality cult that it's no longer surprising that he expects every bad

00:01:20.940 situation to turn to his advantage and perhaps this one will too we'll just have to wait and see

00:01:27.220 i would definitely be happier if he were being prosecuted for something related to january 6th that

00:01:33.680 is for something where there really is no comparison to make to any other political figure alleging a

00:01:38.580 double standard it seems clear that such comparisons in this case are specious because while they

00:01:44.340 mishandled documents clinton and biden and pence did not behave the way trump has behaved here but the

00:01:52.040 political optics are very easily distorted and are actively being distorted now anyway i'm going to keep

00:02:00.280 my powder dry on trump i was hoping never to think about the man again but it seems it will be unavoidable

00:02:06.660 as the 2024 presidential campaign gets rolling but i will pick my moments carefully because the man has been

00:02:15.300 an almost miraculous opportunity cost for our entire species i mean more time has been wasted on trump

00:02:25.300 than on any other human being in the last century i mean this is not hitler or stalin or einstein right

00:02:35.520 this is a person so totally without consequence or substance this is a person whose ideas and

00:02:44.100 life example and even his bad intentions are so measly it really is a perverse miracle that he has taken

00:02:53.900 up this much of everyone's time it's like we just spent the better part of a decade obsessing about

00:03:01.040 and watching our society tear itself apart over vanilla ice or carrot top or peewee herman and i don't

00:03:11.480 mean to denigrate those guys especially but i'm sure each of them would be astounded if they bent the arc

00:03:18.680 of human history in this way on the basis of their cultural products how did we get here how is this the

00:03:27.840 person who has taken up all of our bandwidth it really has been an astonishing theft of our collective

00:03:35.180 attention something seems to have gone very wrong with our culture what we have in place of sober

00:03:43.840 thought it's just a ripping sound that started somewhere around the oj trial at least that's when i first

00:03:51.920 heard it and with the birth of the internet and social media it has grown deafening we seem to have

00:03:57.520 collectively produced an approach to politics and journalism and activism and citizenship a whole

00:04:05.460 life philosophy that really could be summed up in johnny cochran's immortal lie if the glove don't fit

00:04:13.380 you must acquit right i mean that's the level that's the empty slogan that led millions of people

00:04:20.840 to celebrate the release of a man who everyone knew was a murderer that's the level of cynicism

00:04:28.200 and moral confusion and grievance entrepreneurship that seems to have spread everywhere now right left

00:04:36.500 and center and we now have a culture that simply cannot produce a coherent vision of how to survive

00:04:44.220 in this century much less thrive in it because we've lost the ability to impartially talk about

00:04:50.360 facts and most of the people who are lucky enough not to have to really worry about this at least not

00:04:55.620 yet those who are doing well enough to avert their eyes and just focus on their own lives these people

00:05:00.840 are busy watching asmr videos and taking ice baths it seems pretty clear that the mainstream media can't

00:05:07.880 figure out how to solve this but the independent media can't either podcasts and newsletters are

00:05:13.600 becoming like multi-level marketing for conspiracists i've called this a new religion of contrarianism but

00:05:20.900 calling it a religion is too grand right it's a cargo cult that is dazzled by each new meme that washes up on

00:05:28.900 twitter epstein didn't kill himself george soros is ruining everything ufos have finally landed big tech censorship

00:05:38.800 is the most important problem on earth behind every one of these things you get a glimpse of

00:05:45.340 how the story ends with another wave of lunatics storming the u.s capital only to take selfies and 0.99

00:05:52.660 smear shit on the walls i think if jesus came back to earth tomorrow to raise the dead half of our society 0.99

00:06:01.380 would expect him to say something about mrna vaccines or jewish control of the media 0.99

00:06:06.820 can someone figure out how to reboot this hard drive

00:06:10.760 anyway today's podcast has nothing to do with any of these issues

00:06:15.920 today i'm speaking with andy clark andy is a professor of cognitive philosophy at the university

00:06:22.280 of sussex and he's the author of several books most recently the experience machine how our minds

00:06:29.300 predict and shape reality and we talk about the predictive brain as well as embodied cognition

00:06:36.020 and what he calls the extended mind we discuss the structure of perception novelty precision pain

00:06:44.360 psychedelics emotion hacking our predictions hypnosis meditation artificial intelligence consciousness

00:06:53.880 and other topics and now i bring you andy clark

00:06:58.500 i am here with andy clark andy thanks for joining me it's a great pleasure to be here thanks for having

00:07:09.580 me so um you have written a fascinating book titled the experience machine how our minds predict and shape

00:07:17.280 reality and uh long before that you were uh i believe the co-author with david chalmers of the

00:07:25.080 extended mind hypothesis which uh rattled some minds extended or otherwise in philosophy uh back in the day

00:07:33.700 so i want to talk about all this so i guess let's start with your book which mostly focuses on the uh predictive

00:07:42.220 brain hypothesis which is a topic that has come up in at least one recent podcast but let's see if we can

00:07:49.860 explain this fairly counterintuitive thesis but actually before we do look maybe can you just

00:07:57.440 summarize your intellectual background i just gave two landmarks on it but what what have you tended to

00:08:04.280 focus on and and how how do you describe your interest in philosophy and science at the moment okay yeah so you

00:08:10.960 know i've been working in cognitive science and kind of uh philosophy of mind for a long time now

00:08:16.620 originally i guess i was most interested in questions about the role of the body in the

00:08:23.040 construction of our mental life and i'm still very interested in that i soon became interested in

00:08:28.840 connectionism and robotics because that all seemed to go together you know connectionism that old word

00:08:34.020 for artificial neural networks and at some point during that sort of journey the extended mind story

00:08:40.560 came on the scene which i saw really is just a kind of footnote to a lot of work that was going on in

00:08:46.400 embodied cognition anyway it was just a kind of observation that embodied agents can lean on their

00:08:52.740 tools and technologies in such a strong way as to make them worth counting the single systems at times

00:08:58.980 and really i spent a long long time thinking about all that stuff but people kept asking me

00:09:04.240 so what is it that brains do in all of this and you know although i'd followed the neuroscience i'd never

00:09:09.900 bothered to sort of um really look for a systematic account of what the brain's role in these complicated

00:09:16.580 brain body world nexuses was and then when predictive processing came along something i'd kind of been

00:09:23.540 interested in actually since the mid-90s when i was looking at just a fragment of that work that just

00:09:29.720 seemed to be a very very good place to start to weave it all together because it turns out or at

00:09:34.660 least this is what i believe that predictive brains are the perfect internal platform for embodied

00:09:41.040 extended minds so it was nice to get all of those things coming together but that's kind of how it went

00:09:45.800 for me sort of interested in empirically informed philosophy of mind running that through artificial

00:09:51.960 neural networks embodied cognition robotics uh extended mind and here we are today predictive processing

00:09:58.720 nice well a lot of that has relevance for recent developments you know cultural developments with

00:10:05.400 respect to artificial intelligence i think since you published your book ai has just exploded into

00:10:12.220 relevance for almost everyone so uh i think we'll land there and just uh get your take on on the

00:10:19.880 implications of of these increasingly powerful tools but before we do let's talk about the brain and the

00:10:26.920 mind and this notion that much of what the brain is doing perceptually as a matter of motor control and

00:10:35.780 emotional regulation and just cognition generally is a matter of it's predicting reality on some level and

00:10:46.000 then reducing prediction error let's just take it from the ground up however you want to start

00:10:52.580 what is this predictive brain hypothesis yeah i mean i think the i think the best way into it is on the

00:11:00.420 perception side it's going to be important very rapidly that it's not just a story about perception

00:11:06.300 but somehow that seems to me to be the the easiest way to get the general picture so if i was to for example

00:11:14.720 show you a hollow face mask that was lit from behind so you're viewing the concave side of the mask

00:11:22.580 it will actually look to you as if the nose is facing outwards that's called the hollow mask illusion

00:11:28.280 so pretty popular you can see it on the web what seems to be going on there is that our brain has a very

00:11:35.080 strong history with faces and it's come to predict unconsciously very strongly that noses are going to

00:11:44.220 stick out so in that particular case you've got perfectly good sensory information coming in

00:11:50.240 specifying concavity but your visual experience is as of an ordinary sort of convex outward facing nosed

00:11:58.500 face and that's what constructs your experience and i think that's just a sort of a

00:12:04.120 a very small version of what brains are doing all the time so you know that's a case where the

00:12:09.860 stimulus is a bit weird but even in the ordinary case of me looking around the room and seeing a

00:12:16.100 coke can and a and a coffee mug in front of me that is being constructed by my brain having very good

00:12:24.180 predictions about what those sensory stimulations are likely to be like and using those to do an awful

00:12:31.020 lot of work it's cleaning up the signal it's discarding some bits it's amplifying others

00:12:36.080 and it's that process of kind of cleaning up and making sense that downward flowing predictions

00:12:43.580 predictions moving from deep in the brain towards the sensory peripheries seem to be doing all the

00:12:49.480 time that's the general idea these predictions are issued by generative model just like in the in the

00:12:54.860 ai systems that you were just talking about chat gpt and the rest obviously the content of this

00:12:59.980 generative model is rather different to the content of their ones and that's something we might we

00:13:04.560 might come back to in the end but that's the sort of basic picture is we've over time built up a model

00:13:12.040 of how the sensory stimulations ought to be if we're where we think we are doing what we think we're doing

00:13:17.960 and the brain uses those predictions to structure the inputs and then we're driven by the errors in that

00:13:26.100 attempt at structuring so sensory information gets swapped for prediction error rather an early stage of

00:13:34.580 processing so that everything that you see here touch and feel is kind of framed by these attempts at

00:13:40.620 prediction so what is happening in the case where we perceive something that is truly novel right an

00:13:50.420 object that you have never seen before and you have never seen anything quite like it suddenly is

00:13:56.000 placed in front of you next to the coke can what is novelty on this theory yeah i mean i think the right

00:14:04.340 thing to say there is it's going to be very very counterintuitive at first which is that i don't think that

00:14:09.800 we could even perceive absolute genuine novelty but the good thing is that we're never presented with

00:14:16.560 absolute genuine novelty even if an object came from mars or somewhere like that and it landed beside

00:14:22.640 the coke can there's enough common patterns there in the sort of low level sensory information for me to

00:14:30.220 construct some kind of grip on its sort of rough shape and its color at the same time if you put me in a

00:14:36.240 brand new kind of environment the closest i can think of to this is is when i first went diving

00:14:41.280 and you know you remember that experience i find it very very hard to kind of see anything and yet over

00:14:48.360 time you you're able to see an awful lot better and i think that what's going on there is that

00:14:54.280 we have to train what in that case is a very very bad prediction machine in particular with perception

00:15:00.820 action loops so i think if you're going to get to grips with something that is pretty novel

00:15:05.220 then you're going to have to slowly deal with it over time and you're going to have to deal with it

00:15:10.400 in a way that has perception action loops right at the heart i think it would be quite difficult to get

00:15:16.400 on top of these things with sort of just passive information although of course some kinds of system

00:15:21.260 can do that if they have the right training so what am i saying here about about genuine novelty

00:15:26.060 i think the the cases you're thinking of just aren't genuinely novel you know if you blindfold me

00:15:33.280 take me out somewhere i don't know i don't know what country i'm in i open my eyes i still got an

00:15:38.560 awful lot of good predictions that get very very rapidly updated by a little bit of prediction error

00:15:44.060 that might say something like oh i don't know this is this is a very outdoor countryside environment

00:15:50.220 you're in or this is a very industrial urban landscape that you're in and so those early prediction errors

00:15:57.240 whatever i started prediction predicting the early ones can then sort of frame more and more refined predictions

00:16:04.460 so a quick sort of very rapid cycle of predictions and error exchanges settles on on the right thing

00:16:12.780 it's also provable that you can start a prediction machine with random assignments and if you just

00:16:20.600 give it time as it were give it enough training then it will learn a model that can make the right

00:16:25.580 sorts of predictions so you basically got two choices you either retrieve a better prediction now

00:16:30.760 because you've got one or else you do a lot of slow and tortuous learning

00:16:35.680 what is the actual claim here with respect to the error term yeah i mean that so i don't think that

00:16:45.520 we experience prediction errors that's slightly contentious some people think that that perhaps

00:16:51.220 we do in some way i think that what we experience is the result of getting rid of prediction errors

00:16:56.320 so you know your brain has to make a prediction there will be prediction errors but they're not

00:17:02.580 experienced they're the things that let the brain recruit a better prediction so yeah if i open my

00:17:08.960 eyes and i think i'm in my bedroom and i'm actually somewhere else entirely then i don't experience the

00:17:14.060 errors although i might experience a moment or two of confusion a moment or two of uncertainty i think

00:17:20.200 so in that way you know it's not like the error is not there in phenomenology but the but it's not

00:17:26.600 really structuring my experience all structured experience is the best current prediction i think

00:17:33.200 that's that's the right thing to say so then what's the relationship of attention and precision

00:17:38.480 to this picture so precision is a huge weight in a huge player in this in this whole economy it's kind

00:17:48.000 of implementing attention the idea is that precision weightings implement attention but the it's basically

00:17:56.100 just the thought that if you're making predictions and you have sensory information coming in then

00:18:02.500 there's a question how much do i trust the prediction how much do i trust the sensory information

00:18:07.200 and that's what that weight in uh that weight in variable is doing it's just it's able to adjust the

00:18:15.040 amount of processing that is driven by the sensory input versus the predictions so if i'm fairly

00:18:21.920 confident of my predictions as my brain was in the case of the hollow mask illusion for example it's

00:18:28.100 very confident of those predictions and then i end up with uh actually a false visual experience

00:18:33.880 as a result so attention in this case increased attention to the face here is a matter of giving a

00:18:43.320 higher precision weight into the sensory input so as to overcome the illusion yeah attention here can work

00:18:51.400 either way so you know you can be up in the value of the sensory information or you can be up in the

00:18:58.320 value of the prediction according to which of the two your brain is unconsciously estimating to be the

00:19:03.620 most reliable and you know often it will also be a mixture of the two at different levels of processing

00:19:09.000 different areas of the brain so the other things remember about precision here is it's being estimated

00:19:14.520 for every neural population in every area all the time so it's not really just one balancing act it's

00:19:21.440 these you know thousands of little balancing acts all the time but yeah that's the thought is that

00:19:27.400 attention just is the process by which precision gets assigned okay so i want to do our best to make

00:19:35.320 this intuitively graspable for people just in their direct experience so you know i'm now looking at my

00:19:41.400 computer it's a very static scene i've got a word doc open and i've got my desktop and nothing this

00:19:49.620 nothing's moving nothing's changing and i've been looking at it for some minutes so my sensory experiences

00:19:56.620 is fairly stable obviously i've been executing lots of eye movements across this stable scene so this it's

00:20:05.440 it is changing but it's not the ordinary circumstance of a a rapidly changing world that i'm engaging with

00:20:13.340 so i'm looking at the static scene and i find that i can pay attention i can wait various and speaking just

00:20:21.400 visually now i can i can wait the significance of various parts of my visual field over others

00:20:27.260 and i can do that whether i'm actually redirecting my eyes and and putting you know foveal focus on

00:20:33.940 specific parts of it or i can do it just purely as a matter of attention which is to say that i can be

00:20:38.540 focusing i can have my foveal focus on just one word in my document but i can also be attending to the

00:20:46.940 periphery of my visual field you know as a matter of just directing my kind of the beam of my conscious

00:20:54.260 perception and in the midst of all of this it's still possible for something new to appear right

00:21:02.760 so it was not anticipated so i can see like you know scintillas of light that are you know kind of

00:21:10.060 happening more at the level of uh you know my my eye and you know it's like a hardware error as opposed

00:21:17.200 to something that's a genuine perception from the environment you know or it can be like a a floater

00:21:22.520 you know in the liquid of my eye will come across my visual field what is happening is it can you

00:21:28.420 just map this on to the notion of error and the notion of prediction you know when i'm moving from

00:21:36.160 everything that's static that i can continually you know visit and revisit and it's unchanging

00:21:42.140 and the changing term of let's say something floating across my visual field that wasn't there a second

00:21:48.520 how is prediction and error uh accounting for this experience yeah i mean there are there are lots of

00:21:56.940 different things going on there i think one thing to say is that there are there are there are some

00:22:01.740 kinds of stimulus stimulus that get assigned very high precision when yet they're detected at all so

00:22:09.580 fast moving things from the peripheries tend to be assigned high precision as soon as they turn out

00:22:15.840 that's you know that's uh an evolutionarily useful thing you notice something if it's kind of moving

00:22:21.360 fast towards you can you just define that phrase high precision oh sorry this is just highly weighted so in

00:22:29.460 this case it will be the sensory information so that sensory information would then be highly enough

00:22:34.320 weighted to probably break through from whatever else it is you're doing so that you see that thing

00:22:40.840 move you don't you don't always you know if people set up the experiments in in certain ways so that

00:22:45.620 you're very busy trying to solve some other problem somewhere else on the screen you might you might miss

00:22:50.600 it but fast moving things tend to attract precision and that you see will tend to uh to make them

00:22:56.940 noticed in that way the other thing that i think is worth saying about what attention does is it kind of

00:23:04.300 reverses something that happens otherwise fairly automatically in predictive processing which is

00:23:11.620 that well predicted things tend to be dampened and so you know as you get the same information

00:23:18.120 on and on it sort of dampens and that's uh probably what's going on in troxelofaden and things like that

00:23:24.140 where a stimulus begins to kind of fade from view if you don't move your eyes around really enough to

00:23:30.760 give you a little bit of change there so what attention seems to do is it reverses that that

00:23:37.520 dampening effect so that you can keep something alive by by attending attending hard to it and that's

00:23:44.240 some work that uh cock kok and and some others have have done so i don't know i feel like there's

00:23:50.880 something else that you're after here about the way that precision weighting works i mean it's it's

00:23:56.640 basically just sort of applying the sort of estimation of the inverse variance of the of the

00:24:02.760 well actually the prediction error is the thing that is is is typically targeted there so i it's how

00:24:09.140 much am i going to trust prediction errors of this kind as they're emerging right now and that's um just

00:24:16.020 something that the generative model has to learn to estimate in the same way that it's trying to

00:24:20.880 estimate what's out there so one of the things i think is interesting about predictive processing

00:24:26.800 architectures is that they're automatically metacognitive architectures as well there's

00:24:32.620 these two things going on guess the world and guess how good your guessing is all the time

00:24:37.560 and how does this account for other aspects of experience like emotion and motor behavior

00:24:49.120 and i mean maybe we want to do and take each of these at a turn and i'm thinking especially things

00:24:55.400 like pain and i mean there's there's this wide literature on things like you know placebo and

00:25:02.280 nocebo effects and you know pain and functional illness being in many cases driven by one's expectations

00:25:10.200 you have you have a you know fairly arresting example in the book of just how far this can go

00:25:15.860 i mean we can take those in any order you want but i'm thinking about pain and emotion and and

00:25:21.880 motor movement yeah i think um where to start there i think pain let's start with pain and then and then

00:25:29.740 move along to emotion and uh and movement yeah i mean you could think of pain in the same ballpark

00:25:35.060 as emotion but uh but let's just start start with simple pain so you know the idea there is that

00:25:41.480 we're predicting not just the external world but the signals from our own body all the time in fact

00:25:47.360 you might think that predicting the signals from your own body is evolutionarily the whole important

00:25:52.700 thing about about this kind of structure is that you're you're predicting how your body ought to be

00:25:59.920 right now and that helps to kind of in a way that we'll describe in a minute move your body around

00:26:05.680 and adjust internal parameters and you know start sweating and things like that or go and get a

00:26:11.260 something to drink or something to eat in ways that keep those those variables within the bounds of

00:26:17.580 viability so we kind of um we use predictions to make sure that we don't have to stray right outside

00:26:24.140 the bounds of viability before we know something's going wrong that seems you know basic homeostasis and

00:26:29.940 allostasis that's uh i think the fundamental reason why we have predictive brains is to

00:26:36.200 enable those things to happen so just as a concrete example so thirst is not necessarily a reporter of

00:26:45.440 a true departure from homeostasis it's more of a prediction of a coming departure and therefore you

00:26:52.500 deal with the thirst before in fact it's physiologically real yes that's exactly right um

00:26:59.080 lisa feldman barrett describes this very nicely in her um i think it's how emotions are made book

00:27:05.320 where she says that if you feel thirsty and you take a drink of water you'll you immediately feel

00:27:12.240 as if your thirst is quenched but actually the water won't do you any good for about 20 minutes

00:27:17.020 anything like that but that's fine because the feeling of having a quenched thirst reflects a

00:27:22.980 prediction just as much as the thirst did in the first place so you've got time to spare if you see

00:27:28.220 what i mean so it's fine to think that it's quenched now because as long as it's quenched in 20 minutes

00:27:33.240 you know you're in you're in good shape so the thought there is that yeah all of our bodily feelings

00:27:39.560 are constructed around predictions including pain and for that reason if you get very strong

00:27:45.960 information suggesting that something very painful is happening to your body then even if nothing is

00:27:52.880 actually happening to your body you feel intense pain you know i think the example you might be

00:27:57.440 thinking of in the book is a construction worker that fell from a height onto a nail and it appeared

00:28:05.320 to pierce right through their foot they were in intense agony they were taken to hospital and given

00:28:10.700 fentanyl and then when they slowly removed the nail from from the the foot well it turned out it had just

00:28:16.760 passed harmlessly between the toes but of course the worker couldn't see that they're wearing a big

00:28:22.100 work boot what they saw was strong visual evidence of a really really nasty injury and i have absolutely

00:28:28.480 no doubt that the pain was perfectly real and intense intense enough for the fentanyl and that's sort of

00:28:35.020 you know you might think that's a very dramatic case but the moral of the story and the moral of the

00:28:41.040 discussion in the book anyway is that actually all of our pains and all of our feelings are constructed

00:28:47.400 in part from prediction and in part from sensory evidence and that's as true for ordinary pain as it

00:28:55.620 is for that particular sort of a rather dramatic illusion of pain and then you've got all the

00:29:02.580 complicated functional medical syndrome conditions in between where in some cases there's no sufficient

00:29:10.920 physical cause but in many cases there's a physical cause but it's just not a sufficient explanation

00:29:17.860 of the the intensity or persistence of the pain or other disability and there it just seems like

00:29:26.060 there's a little bit of overweighted prediction machinery in play and there's a lot of interest

00:29:30.380 in new therapies that are trying to target the predictions rather than anything else so i think pain is you

00:29:38.020 know we all know this in a way it's sort of if the dentist says expect a tickle they're saying that

00:29:43.300 for a reason they're trying to frame those sensations that you're going to get in a way that really will

00:29:49.160 dampen the the experience of pain just a little bit and there are controlled experiments showing that

00:29:56.360 expectations of intense pain will up the pain rating and expectations of less intense pain will down the pain

00:30:04.400 even when what's being delivered is you know an intermediate stimulus all those times so i think

00:30:12.080 pain's pain's a good case but it's just uh it's just one that we all happen to know about but all of

00:30:16.760 our medical symptoms all of our bodily experiences are built up in this way i just want to revisit the

00:30:23.300 basic thesis again because i i know you clarified this at the outset but um i just want to make sure i

00:30:29.740 have the true shape of it so is the claim that we mostly consciously experience our predictions and are

00:30:41.240 continually revising them in concert with attending to sensory inputs or is it that all we experience

00:30:50.300 is our predictions and that the the sensory input is really always unconsciously modifying

00:30:57.020 our predictions and that's that is it's it's it's a as anal seth called a controlled hallucination but

00:31:04.080 it's yeah the control component is always in the happening in the dark yes that's the way i see it

00:31:11.380 of course you know it's it's still early days for for this sort of family of theories and you could

00:31:19.420 construct them in in different ways so that you have some sort of somehow partial experience of the

00:31:25.620 the flow of the prediction errors but that's not true to my visual experience normally for example

00:31:31.300 if i just turn my head around and see the room that i'm in there must be flurry upon flurry of

00:31:37.320 prediction error being created and then being resolved because i know about the room i know about the kind

00:31:43.160 of objects in it i have no trouble at all sort of upping the attention on that diary on my desk and

00:31:48.880 seeing the details of the sunflower that seems to be um on the on the front cover i don't experience

00:31:55.780 the errors at all i just experience the the most successful predictive model that has accommodated

00:32:03.140 as much of the error as can be accommodated right now so what's happening uh under conditions where

00:32:09.220 someone has taken a powerful psychedelic say like lsd or psilocybin you know there's there's a i i know that

00:32:16.960 you discuss this a little bit in the book and there's robin carhart harris's thesis around this

00:32:22.120 how do you think about this within the schema of prediction and and error terms yeah i mean the

00:32:32.200 the basically in the book i just adopt the carhart harris model i think it's the best one that we've

00:32:37.460 currently got but i think the first thing to say about the the actions of psychedelics is it's very

00:32:42.540 dose dependent as i guess we hope as you will know if you take any of them is very dose dependent

00:32:48.340 and that and the varying effects at different doses actually fall out quite nicely from the idea that

00:32:57.880 the brain is a multi-level prediction machine where the lower levels are specializing in stuff a lot

00:33:03.660 closer to the sensory information itself so you know obvious things you know color shape texture those

00:33:10.760 sorts of things and then the higher levels are dealing in much more abstract things like um i know

00:33:16.660 what kind of thing is this what can i do with it in the case of many of the predictions that seem to be

00:33:23.060 kind of targeted by the psychedelics at the low levels you get sort of visual disturbances you might

00:33:30.080 see creeping forms different textures strange colors but then at the higher doses you get the really

00:33:36.080 interesting effects like um ego dissolution and uh oneness with the universe and uh the kind of um

00:33:43.620 the beneficial effects on people with chronic depression for example all of those things seem to require

00:33:50.180 higher doses not repeated doses necessarily one dose can often do it and that falls into place

00:33:56.320 according to carhart harris i just report the work here because the actual sort of shape of the

00:34:02.980 psychedelic molecules causes them to bind to receptors are higher up in the in the processing

00:34:10.580 stream meaning that they're gonna have more effect at high doses on the stuff that is more abstract if

00:34:18.720 you like so think about things like you know what's your relationship to the world what's your

00:34:22.640 relationship to yourself you know how do you how do you how do you see yourself in the future

00:34:28.620 so i think it's it does make a certain kind of sense the idea that we've got this sort of cascade

00:34:33.020 and that if you can sort of i think the phrase that he uses is shaking the snow globe so the idea

00:34:41.740 there is that you can sort of disrupt the ordinary entrenched predictions at those high levels and that

00:34:47.500 can be really really liberating because you get to experience the world in a new way one that um

00:34:53.180 you know experience your your being in the world in a new way which i think can be incredibly powerful

00:35:00.080 for people with sort of you know end of life anxiety or depression and so on that's what the

00:35:06.600 research seems to suggest but in that case where it seems like one is experiencing a great onrushing

00:35:14.600 of novelty what is one actually experiencing with respect to these different components of the theory

00:35:22.380 that you know the raw sensory data versus one's prediction about what is happening in the world and the

00:35:29.760 accuracy the prediction about the validity of one's own prediction yeah i think the snow globe that's where

00:35:36.180 the snow globe image is quite useful i think because a good way to think about it is that what's going on

00:35:42.500 when you get that sort of onrush of novelty as you as you nicely put it there is really the relaxation

00:35:49.440 of entrenched predictions so it's kind of getting rid or temporarily at least of the predictions that

00:35:56.900 were gathering the sensory input into the accepted buckets and since it's not being gathered into the

00:36:02.700 accepted buckets then new patterns can be detected new shapes can form it's not that they form without

00:36:09.960 the benefit of predictions it's just that the predictions that can now be recruited to deal

00:36:15.220 with that information are not the ones that were being recruited before and you know i think that's

00:36:20.620 i think that's the best way to think about that and why the shaking up the snow globe thing is it's quite

00:36:25.600 useful little uh little picture now do you have personal experience with any of these drugs

00:36:32.000 uh yeah some of them not um yeah i've i've had some i've had a fair bit of experience with mdma which

00:36:39.920 is a borderline not a classic psychedelic i took peyote once a long time ago that's uh that's in the

00:36:45.760 in the classic psychedelic uh psychedelic mode and of course magic mushrooms um magic mushrooms grew

00:36:52.440 all around the campus when i was an undergraduate so yeah we have plenty of those uh so so yeah some of

00:36:58.400 them at least well that's a good goad to philosophy yeah that's true yeah we'll say well mdma as you

00:37:05.560 point out is not a classic psychedelic but it's it leads nicely to a any discussion of emotion and

00:37:13.920 emotional pain and its antithesis um how do you think about emotion in this context yeah so i think

00:37:22.940 that emotion has a very strong component of bodily prediction in it i mean it's not just bodily

00:37:28.760 prediction but there's a sort of there's an old picture of emotion that goes back to william james

00:37:34.280 i'm sure that you know it and you know many of your listeners know it it's this idea that that what an

00:37:39.660 emotion is is a sort of perception of the bodily changes that are associated with something or the

00:37:46.040 ones that are going on right now i should say so you know the example the famous example is you see a

00:37:51.620 bear and you feel fear and you run from the bear but the feeling of fear is actually your perception

00:37:58.860 of the bodily states of kind of arousal and preparation for flight and whatever else you know

00:38:05.880 galvanic skin response that happens that's a sort of motivated there by the idea that if you took all

00:38:12.440 that away you might judge that it would be a good idea to run away but you wouldn't really be feeling

00:38:18.460 anything and i think that that that story has a lot going for it but it's a little bit blunt i mean

00:38:25.740 so my colleague at sussex hugo critchley has done a lot of work on this and uh what they find is that

00:38:32.280 from the james model you you might kind of expect there to be a one-to-one mapping between every emotion

00:38:37.960 we can feel and the perception of some set of bodily changes but there doesn't seem to be that

00:38:43.660 you know it's as if the bodily changes are a bit blunt um you know is there a characteristic signature

00:38:49.980 for i don't know the anxiety that i was feeling before this podcast versus the anxiety that maybe

00:38:57.260 i'm going to feel if i'm about to jump off a high diving board or you know it's just a bit blunt to

00:39:02.500 reconstruct all of that but if what you're doing is chucking that information into one big pot along

00:39:09.000 with what you know about the context in order to try to predict what's going to be happening in your

00:39:14.780 body and the world over the next let's say you know a few few minutes then you get something that

00:39:20.600 is much more fine-grained so you know the the feeling of a fast beating heart when you're working

00:39:26.000 out at the gym versus when you're just sitting down and you're having a panic attack or you're worried

00:39:31.100 that you're having a heart attack or something like that you know these are these are very different

00:39:35.680 feelings and yet the bodily stuff you're picking up on might be very very similar yeah well people

00:39:41.400 will be familiar with the concept of reframing that is um really a kind of an opportunity afforded

00:39:49.020 based on the way in which cognition and emotion interact there so you as you just point out the

00:39:57.380 same sensations can be arising in very different contexts and predictive of very different experiences

00:40:03.200 and and that gives some leverage to us as far as he kind of hacking our own yeah you know reactions

00:40:09.720 by just consciously reframing or and or even just comparing two similar states of arousal and noticing

00:40:17.020 that they're you know the in the one case you're scoring it as a highly negative experience in another

00:40:23.400 it's it can be quite positive i mean say you know the example i always use is the stress one feels

00:40:29.240 in the gym at the most intense part of one's workout just viewed purely as a matter of physiological

00:40:35.660 stimulus is a you know it would be an extraordinarily negative and even terrifying state of the body if

00:40:43.560 you didn't know the reasons for it you know if you woke up at three in the morning and you felt that way

00:40:48.700 you'd call an ambulance but because you know what's going on and you know what precipitated it

00:40:53.640 it's actually a it's a highly positive experience for most people even if there's an unpleasantness to

00:40:59.620 it yeah so how do you think about the freedom this gives us to intervene in our standard predictive

00:41:08.620 weightings that may be making us frankly miserable and improve our lives on the basis of just grabbing the

00:41:16.580 the levers of this machinery yeah i mean actually just just before i pick up on that something you

00:41:22.700 said there that i i think is interesting to follow up a bit is whether we should think about the feeling

00:41:28.420 as the same but the judgment of its importance as being different or whether the actual feeling

00:41:34.700 when you frame it as i'm working out at the gym versus when you frame it as i've just woken up in bed

00:41:41.460 and i don't know what's going on i think that the predictive processing story says that the feeling

00:41:45.840 itself is different it's not that you've got the same feeling both times and context just allows

00:41:51.400 you to behave differently in response it's reaching further than that somehow it's really changing the

00:41:57.220 feeling well i think i think it's important to bear that in mind yeah i think well i think both could be

00:42:02.540 true here because it i would certainly agree that subsequent feelings get layered onto it based on the

00:42:08.800 interpretation so every it's obviously a moving target but if you're i mean you're going to get a

00:42:14.120 a cortisol dump you know based on the three in the morning experience of you know pressure and

00:42:20.500 and elevated heart rate which you wouldn't get in the gym because you're not you know reacting to

00:42:27.440 this thing and this is definitely evolving yeah no you're right naturally it's so important to

00:42:33.080 always think about everything over time and it is so tempting to sometimes go back and just think

00:42:38.740 about snapshots but i really think if we're looking at cognition we should always be thinking over time

00:42:43.940 so yeah thanks for that that's that is really important you did ask also there about um ways to

00:42:49.840 intervene yeah you know what we what could we do to leverage um this wiggle room that we've got in our

00:42:55.340 favor and i think that you know once we realize that the wiggle room is built around these edifices of

00:43:03.100 prediction then we can begin to see things to do the the thing that is a sort of break on that is that

00:43:09.140 so much of that prediction machinery is unconscious and sort of we can't control it just by having a

00:43:16.860 different thought so you know when i look at the hollow mask for example i might very well be able to

00:43:22.660 think to myself look i really really really know that that's a hollow side that's facing me it's just

00:43:27.720 not going to do any good you know i can't reach down and alter those but maybe i could with enough

00:43:33.160 practice or looking at things in different lights you know it kind of depends things vary according to

00:43:38.920 how a different illusion is being uh being generated but in the case of things that we might do in our

00:43:45.040 daily life the obvious cases are things like reframing an experience that might otherwise be

00:43:51.780 negative and that that negativity would set off bad cycles so you know if i'm a if i'm about to do a

00:43:59.000 talk i sometimes feel a little tingle in my fingers i guess that's adrenaline or you know something like

00:44:03.660 that reframing that tingle not as anxiety but as chemical readiness to deliver a good performance

00:44:09.560 is actually a trick that i think works it really does seem to do something likewise reframing pain that

00:44:16.040 we talked about earlier all of those self-affirmation practices that we read about now they actually have

00:44:22.820 there's some pretty good evidence that they can make a difference in some cases so there's some good

00:44:28.860 studies showing that self-affirmation about abilities to do spatial reasoning tasks and math tasks

00:44:36.260 can abolish gender differences in uk school kids in that case and there was a similar set of results with

00:44:43.040 race differences in u.s school kids so you know these are nothing is a panacea and nothing works

00:44:49.880 for everything you've got to have the basic skill set otherwise you can't unleash it but um but if you

00:44:55.900 do have the basic skill set you can either get in your own way or get out of your own way and

00:45:01.300 framing and self-affirmation really seems to help with getting out of our own way what about hypnosis

00:45:06.860 yeah that's another wonderful way of getting out of our own way actually another of my colleagues

00:45:11.820 zoltan the wonderfully named zoltan deans works on hypnosis and cognitive science and um and yeah

00:45:18.580 i think you know hypnosis is is a powerful and actually under exploited tool at the moment it's

00:45:25.980 also a a nice way of you know susceptibility to to hypnosis is an interesting sort of um gauge as

00:45:35.060 zoltan says of what he calls phenomenological control so the amount of control that you can

00:45:41.700 exert over the shape of your own experience by these different techniques probably varies according

00:45:47.940 to how hypnotizable you are yeah yeah and and i guess differences in hypnotizability

00:45:52.960 is a a measure of the plasticity of one's models right or their susceptibility to you know conceptual

00:46:04.220 uh influence right i mean how how would you on on the basis of of this thesis how would you describe

00:46:10.440 because you know famously there's there's a very wide range in susceptibility to hypnosis

00:46:14.640 there's the stanford scale which i think goes from one to nine or zero to nine and uh you know some

00:46:21.000 people just are not hypnotizable and some people are are highly so uh how would you describe that

00:46:27.400 difference in light of the model yeah i think it has to be related deeply to the amount of sort of

00:46:34.540 voluntary control you can exert over your own precision weightings just to dip into the into

00:46:39.940 the jargon there but that's uh the amount of control that you can exert over the weighting of

00:46:45.520 top-down predictions over sensory information if you can exert a lot of control over that

00:46:51.900 then as long as you want to be hypnotized you should be able to be hypnotized successfully

00:46:58.200 and of course if you have that sort of control and you really don't want to be hypnotized you

00:47:03.280 won't be able to be hypnotized it's a sort of um as zoltan puts it it's a sort of voluntary

00:47:08.640 the voluntary giving up of voluntary control or something like that so i think control over

00:47:13.840 precision weighting is actually it's a really really important skill that we humans should try and

00:47:20.120 develop i think that meditation is another way of trying to develop that skill it's you know if you

00:47:27.560 ask me what i think meditation is doing for people i think it is enabling greater control over the

00:47:33.840 precision weighting apparatus and the more control we have over that the more control we have over our

00:47:39.080 own experience do you have much experience with meditation well funny enough i i only have a little

00:47:45.760 because i don't seem to get on with it and i'm really disappointed about this you know i've been

00:47:50.380 to a few sort of week-long courses and uh and i've done my best to sort of you know kind of sit quietly

00:47:56.840 and do the right things for 20 minutes a day for a while are these are week-long vipassana courses like

00:48:02.720 mindfulness yes exactly a sort of live-in kind of yeah i mean it's a pretty obviously i probably should

00:48:09.020 give it particularly given my theoretical views should give it a better shot but because every time i've

00:48:14.140 tried i just seem to be maybe just a little bit too too manic and hyper i the very kind of person

00:48:21.060 would benefit most but finds it hardest to get into have you ever tried at the same time yeah go ahead

00:48:27.880 have you ever tried meditating while on mdma or any other compound of interest no no i've never tried

00:48:34.300 that that might be you think that would be worth a go yeah interesting yeah if um if mdma is still on

00:48:40.320 the menu i would highly recommend trying uh some mindfulness i have never tried that but i have

00:48:47.220 had that experience of you know just sort of sitting and finding myself very very happy looking

00:48:52.940 at a very small thing in front of me which is you know it's got a little bit of that sort of

00:48:58.960 almost unwitting mindfulness about it i i think the closest i get in my current daily life is when

00:49:05.980 i go on very long walks and there's a certain point in in a long walk where you can i think

00:49:11.740 start to enter a state that has some of some of the right properties so again just in an effort

00:49:18.200 however quixotic to make this intuitive for people when you say that you think meditation

00:49:24.920 is a matter of of altering the precision weighting of one's models what can you think it's i think it's more

00:49:33.700 about gaining control over the precision weighting so you know altering is what you do with it once

00:49:39.380 you gain control over it but it it's it's learning how to control the precision weighting better

00:49:45.440 so that for example you can allow the sensory information to kind of try to speak for itself

00:49:51.820 a bit more without being sort of sucked into starting you off thinking about stuff that is coming

00:49:57.900 from the higher more abstract levels like i don't know what am i going to do later today what should

00:50:03.100 i be working on now that sort of stuff so it's um i think it's gaining gaining some control over

00:50:09.920 over the amount of over the way that precision is distributed across the machine this is it's a very

00:50:17.220 difficult thing because most of the precision weighting stuff is happening automatically and

00:50:21.660 beneath the hood all the time so i think that's why we need these sort of long-term practices

00:50:27.700 to to somehow somehow install a bit more control than we would otherwise have well let me describe

00:50:35.200 my experience of mindfulness and and you can tell me how it fits in if you can do this that would be

00:50:42.180 interesting and there there are kind of a few stages to this but let's take anxiety as a classically

00:50:47.720 negative emotion that people find mindfulness can be very helpful with so you know there's something

00:50:54.160 has precipitated anxiety let's say a thought about uh you know some future event like a public talk

00:50:59.800 and you feel this anxiety and it feels intrinsically unpleasant and the default reaction is to not want

00:51:09.160 to feel that way to be thinking about the thing that's making you anxious to be thinking about the

00:51:13.700 reasons why you you don't like this why why am i this sort of person who gets anxious why can't i just

00:51:18.740 be happy to be giving this talk and you're you're thinking the thoughts are kindling the anxiety the

00:51:24.840 anxiety is being felt and and kindling further thoughts in that vein and the way mindfulness

00:51:31.380 breaks this spell is that you remember that it's possible just to feel the anxiety just feel the mere

00:51:38.360 physiology of the the butterflies in your chest and to feel it non-judgmentally and non-reactively you can

00:51:46.900 even feel the intrinsic unpleasantness of it if that's salient but even but feel that without

00:51:52.480 reaction and you can notice that consciousness is just this open space in which everything

00:51:57.660 thoughts and sensations and changes in physiology are just appearing all by themselves so you just rest

00:52:04.680 as that open and non-judgmental and non-reactive awareness of all of these changes and what in the moment you

00:52:13.400 shift to that openness and just mirror awareness they lose their psychological implications so anxiety

00:52:22.840 in some sense is no longer anxiety it's just this changing energy state of the body that doesn't have

00:52:30.540 meaning i mean in this in this moment it no longer has me it has no more meaning than a feeling of

00:52:36.160 indigestion or you know itching on your skin i mean it doesn't get read back into a psychological story

00:52:43.460 of the kind of person you are it's just fluttering and and actually benign changes in the state of

00:52:51.060 energy of the body so given that transition how might you explain what's happening there in terms of

00:52:58.880 precision weighting and and predictive models etc yeah that's uh that's that's a lovely description i think

00:53:05.300 you must be a really really good uh meditation teacher i like the sound of that so i think the thing

00:53:10.640 to think there is that the precision is a zero-sum game so you know if you really up the precision on one

00:53:17.380 place then you have to down the precision elsewhere and so if you now imagine really

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Making Sense - Sam Harris - June 13, 2023

#322 — Predicting Reality

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