Michael Littman: Reinforcement Learning and the Future of AI | Lex Fridman Podcast #144
c9AbECvRt20 • 2020-12-13
Transcript preview
Open
Kind: captions Language: en the following is a conversation with michael littman a computer science professor at brown university doing research on and teaching machine learning reinforcement learning and artificial intelligence he enjoys being silly and lighthearted in conversation so this was definitely a fun one quick mention of each sponsor followed by some thoughts related to the episode thank you to simply safe a home security company i use to monitor and protect my apartment expressvpn the vpn i've used for many years to protect my privacy and the internet masterclass online courses that i enjoy from some of the most amazing humans in history and better help online therapy with a licensed professional please check out the sponsors in the description to get a discount and to support this podcast as a side note let me say that i may experiment with doing some solo episodes in the coming months or two the three ideas i have floating in my head currently is to use one a particular moment in history two a particular movie or three a book to uh drive a conversation about a set of uh related concepts for example i could use 2001 a space odyssey or x machina to talk about agi for one two three hours or i could do an episode on the yes rise and fall of hitler and stalin each in a separate episode using relevant books and historical moments for reference i find the format of a solo episode very uncomfortable and challenging but that just tells me that it's something i definitely need to do and learn from the experience of course i hope you come along for the ride also since we have all this momentum built up on announcements i'm giving a few lectures on machine learning at mit this january in general if you have ideas for the episodes for the lectures or for just short videos on youtube let me know in the comments that i still definitely read despite my better judgment and the wise sage device of the great joe rogan if you enjoy this thing subscribe on youtube review it with five stars on apple podcast follow on spotify support on patreon or connect with me on twitter lex friedman and now here's my conversation with michael littman i saw a video of you talking to charles this bell about westworld the tv series you guys were doing a kind of thing where you're watching new things together but let's rewind back is there a sci-fi movie or book or shows that you that was profound that had an impact on you philosophically or just like specifically something you enjoyed nerding out about yeah interesting i think a lot of us have been inspired by robots in movies the one that i really like is uh there's a movie called robot and frank which i think is really interesting because it's very near-term future where uh robots are being deployed as uh helpers in people's homes and it was it was and we don't know how to make robots like that at this point but it seemed very plausible it seemed very realistic or imaginable and i thought that was really cool because they did they're awkward they do funny things it raised some interesting issues but it seemed like something that would ultimately be helpful and good if we could do it right yeah he was an older cranky gentleman right he was an older cranky uh jewel thief yeah it's kind of funny little thing which is you know he's a dual thief and so he pulls the robot into his life which is like which is something you could imagine taking a home robotics thing and pulling into whatever quirky thing that's involved in your this is meaningful to you exactly so yeah and i think i think from that perspective i mean not all of us are jewel thieves and so when we bring our robots into it for yourself uh explains a lot about this apartment actually but no the idea that that people should have the ability to you know make this technology their own that that it becomes part of their lives and and i think that's it's hard for us as technologists to make that kind of technology it's easier to mold people into what we need them to be and um just that opposite vision i think is really inspiring and then there's a anthropomorphization where we project certain things on them because i think the robot was kind of dumb but i have a bunch of roombas that play with and they you immediately project stuff onto them much greater level of intelligence we'll probably do that with each other too much much greater degree of compass that's right one of the things we're learning from ai is where we are smart and where we are not smart yeah you also enjoy as people can see and i enjoyed myself uh watching you sing and even dance a little bit a little bit a little bit a little bit of dancing a little bit of dancing that's not quite my thing as a as a method of education or just in life you know in general so easy question what's the definitive objectively speaking top three songs of all time maybe something that you know uh to walk that back a little bit maybe something that others might be surprised by the three three songs that you kind of enjoy that is a great question that i cannot answer but instead let me tell you a story so pick a question you do want it that's right i've been watching the presidential debates and vice president debates and turns out yeah it's really you can just answer any question you want so so it's a related question [Laughter] yeah well said i really like pop music i've enjoyed pop music ever since i was very young so 60s music 70s music 80s music this is all awesome and then i had kids and i think i stopped listening to music and i was starting to realize that the like my musical taste had sort of frozen out and so i decided in 2011 i think to start listening to the top 10 billboard songs each week so i'd be on the on the treadmill and i would listen to that week's top 10 songs so i could find out what was popular now and what i discovered is that i have no musical taste whatsoever i like what i'm familiar with and so yeah the first time i'd hear a song it's the first week that was on the charts i'd be like and then the second week i was into it a little bit and the third week i was loving it and by the fourth week is like just part of me and so i'm afraid that i can't tell you the most my favorite song of all time because it's whatever i heard most recently yeah that's interesting people have told me that um there's an art to listening to music as well you can start to if you listen to a song just carefully like explicitly just force yourself to really listen you start to uh i did this when i was part of jazz band and fusion band in college is there's they you you start to hear the layers of the instruments you start to hear the individual instruments and you start to uh you can listen to classical music or to orchestra this way you can listen to jazz this way i mean uh it's funny to imagine you now to walk in that forward to listening to pop hits now as like a scholar listening to like cardi b or something like that or justin timberlake is he no not temple like bieber i guess they've both been in the top 10 since i've been listening they're still still up there oh my god i'm so clueless if you haven't heard justin timberlake's top 10 in the last few years there was one song that he did where the music video was set at essentially nurips oh wow oh the one with the robotics yeah yeah yeah yeah yeah yeah he's like at an academic conference and he and he's doing it he was presenting it was sort of a cross between the apple like steve jobs kind of talk and nurips um so i you know it's always fun when ai shows up in pop culture i wonder if he consulted somebody for that that's very that's really interesting so maybe on that topic i've seen your um your celebrity multiple dimensions but one of them is you've done cameos in different places i've seen you in a turbo tax commercial as like i guess the the brilliant einstein character and the the point is that turbo tax doesn't need somebody like you doesn't need a brilliant very few things need someone like me but yes they were specifically emphasizing the idea that you don't need to be a like a computer expert to be able to use their software how did you end up in that world i think it's an interesting story so i was teaching my class it was an intro computer science class for non-concentrators non-majors and sometimes when people would visit campus they would check in to say hey we want to see what a class is like can we sit on your class so a person came to my class who was the daughter of the brother of the hus husband of the best friend of my wife anyway basically a family friend came to campus to to check out brown and asked to come to my class and and came with her dad her dad is uh who i've known from various kinds of family events and so forth but he also does advertising and he said that he was recruiting scientists for this this this ad this this turbotax set of ads and he said we wrote the ad with the idea that we get like the most brilliant researchers um but they all said no so can you help us find the like b level scientists i'm like sure that's that's who i hang out with so that should be fine so i put together a list and i did what some people call the dick cheney so i included myself on the list of possible candidates uh you know with a little blurb about each one and why i thought it would make sense for them to to do it and they reached out to a handful of them but then they ultimately they youtube stalked me a little bit and they thought oh i think he could do this and um they said okay we're gonna offer you the commercial i'm like what so um it was it was such an interesting experience because it's it's they have another world the people who do like nationwide kind of ad campaigns and and television shows and movies and so forth it's quite a a remarkable system that they have going because like a set yeah so i went to uh it was just somebody's house that they rented in new jersey um but it in the in the commercial it's just me and this other woman in reality there were 50 people in that room and another i don't know half a dozen kind of spread out around the house in various ways there were people whose job it was to control the sun they were in the backyard on ladders putting filters up to try to make sure that the sun didn't glare off the window in a way that would wreck the shot so there was like six people out there doing that there was three people out there giving snacks the craft table there was another three people giving healthy snacks because that was a separate craft table there was one person whose job it was to keep me from getting lost and the i think the reason for all this is because so many people are in one place at one time they have to be time efficient they have to get it done this the morning they were going to do my commercial in the afternoon they were going to do a commercial of a mathematics professor from princeton they had to get it done no you know no wasted time or energy and so there's just a fleet of people all working as an organism and it was fascinating i was just the whole time just looking around like this is so neat like one person whose job it was to take the camera off of the camera man so that someone else whose job it was to remove the film canister because every couple's takes they had to replace the film because you know film gets used up it was just i don't know i was geeking out the whole time it was so fun how many takes did it take it looked the opposite like there was more than two people there it was very relaxing right yeah the super i mean the person who i was in the scene with um is a professional she's a you know uh she's an actor improv comedian okay in your community and when i got there they had given me a script as such as it was and then i got there and they said we're gonna do this as improv i'm like i don't know how to improv like this is not i don't know what this i don't know what you're telling me to do here don't worry she knows okay okay we'll see how this goes i get i guess i got pulled into the story because like where the heck did you come from i guess in the scene like how did you show up in this random person's house i don't know yeah well i mean the reality of it is i stood outside in the blazing sun there was someone whose job it was to keep an umbrella over me because i started to schvitz i started to sweat and so i would wreck the shot because my face was all shiny with sweat so there was one person who would dab me off had an umbrella um but yeah like the reality of it like why is this strange stalkery person hanging around outside somebody's house yeah we're not we're not sure when you have to look in we'll have to wait for the book but are you uh so you make you make like you said youtube you make videos yourself you make awesome parody sort of uh parody songs that kind of focus in on particular aspects of computer science how much those seem really natural how much production value goes into that do you also have a team of 50 people videos almost all the videos except for the ones that people would have actually seen were just me i write the lyrics i sing the song i i generally find a um like a backing track online because i'm unlike you can't really play an instrument and then i do in some cases i'll do visuals using just like powerpoint lots and lots of powerpoint to make it sort of like an animation the the most produced one is the one that people might have seen which is the overfitting video that i did with charles isbell um and that was produced by the georgia tech and udacity people because we were doing a class together it was kind of i usually do parody songs kind of to cap off a class at the end of a class so that one you're wearing so it's a this the thriller yeah you're wearing the michael jackson the red leather jacket the interesting thing with podcasting that you're also uh into is that i really enjoy is that there's not a team of people it's kind of more because you know the the there's something that happens when there's more people involved than just one person that just the way you start acting i don't know there's a censorship you're not given especially for like slow thinkers like me you're not and i think most of us are if we're trying to actually think we're a little bit slow and and careful it it kind of large teams get in the way of that and i don't know what to do with ice like that's the to me like if you know this it's very popular to criticize quote unquote mainstream media i but there is legitimacy to criticizing them the same i love listening to npr for example but every it's clear that there's a team behind it there's a commercial there's constant commercial breaks there's this kind of like rush of like uh okay i have to interrupt you now because we have to go to commercial just this whole it creates it destroys the possibility of nuanced conversation yeah exactly evian uh which charles uh isabel who i i talked to yesterday told me that evian is naive backwards which the fact that his mind thinks this way is just uh it's quite brilliant anyway there's a freedom to this podcast he's dr awkward which by the way is a palindrome that's a palindrome that i happen to know for from other parts of my life and i just you just throw it out well you know use it against charles dr awkward so what uh what was the most challenging parody song to make was it the thriller one hmm no that was really fun i wrote the lyrics really quickly um and then i gave it over to the product production team they recruited a a cappella group to to sing that went it went really smoothly it's great having a team because then you can just focus on the part that you really love which in my case is writing the lyrics uh for me the most challenging one not challenging in a bad way but challenging in a really fun way was i did one of this one of the parody songs i did is is about the halting problem in computer science the the fact that you can't create a program that can tell for any other arbitrary program whether it actually going to get stuck in infinite loop or whether it's going to eventually stop and so i i did it to an 80s song because that's i hadn't started my new thing of learning current songs and it was billy joel's the piano man nice which is a great song great song yeah yeah and sing me a song you get the piano man yeah yeah so the lyrics are great because first of all it rhymes uh not all songs rhyme i did i've done rolling stone songs which turn out to have no rhyme scheme whatsoever they're just sort of yelling and having a good time which makes it not fun from a parody perspective because like you can say anything but this you know the lines rhymed and there was a lot of internal rhymes as well and so figuring out how to sing with internal rhymes a proof of the halting problem was really challenging and it was i really enjoyed that process what about uh last question on this topic what about the dancing in the thriller video how many takes that take so i wasn't planning to dance they they had me in the studio and they gave me the jacket and it's like well you can't if you have the jacket and the glove like there's not much you can do yeah so i um i think i just danced around and then they said why don't you dance a little bit we there was a scene with me and charles dancing together they did not use it in the video but we recorded it um yeah yeah no it was it was pretty funny and charles who has this beautiful wonderful voice doesn't really sing he's not really a singer and so that was why i designed the song with him doing a spoken section and me doing things very like barry white yeah it's a smooth baritone yeah yeah it's great that was awesome so one of the other things charles said is that you know everyone knows you as like a super nice guy super passionate about teaching and so on uh what he said i don't know if it's true that despite the fact that you're you are cold like okay i will admit this finally for the first time that was that was me it's the johnny cash song the man in reno just to watch him die uh that you actually do have uh some strong opinions on some topics so if this in fact is true what uh strong opinions would you say you have is there ideas you think maybe an artificial intelligence machine learning maybe in life that you believe is true that others might you know some number of people might disagree with you on so i try very hard to see things from multiple perspectives there's there's this great calvin and harp's calvin and hobb's cartoon where cal do you know okay so calvin's dad is always kind of a bit of a foil and he he was he talked to calvin and just calvin had done something wrong the dad talks him into like seeing it from another perspective and calvin like this breaks calvin because he's like oh my gosh now i can see the opposite sides of things and so the it's it becomes like a cubist cartoon where there is no front and back everything's just exposed and it really freaks him out and finally he settles back down it's like oh good no i can make that go away but like i'm that i'm that i live in that world where i'm trying to see everything from every perspective all the time so there are some things that i've formed opinions about that i would be harder i think to disavow me of one is um the super intelligence argument and the existential threat of ai is one where i feel pretty confident in my feeling about that one like i'm willing to hear other arguments but like i am not particularly moved by the idea that if we're not careful we will accidentally create a super intelligence that will destroy human life let's talk about that let's get you in trouble and record your video it's like bill gates uh i think he said like some quote about the internet that that's just gonna be a small thing it's not gonna really go anywhere and i think uh steve ballmer said uh i don't know why i'm sticking on microsoft uh that's something that like smartphones are useless there's no reason why microsoft should get into smartphones that kind of so let's get let's talk about agi as agi is destroying the world we'll look back at this video and see no uh i think it's really interesting to actually talk about because nobody really knows the future so you have to use your best intuition it's very difficult to predict it but you have spoken about agi and the existential risks around it and sort of based on your intuition that we're quite far away from that being a serious concern relative to the other concepts we have can you maybe uh unpack that a little bit yeah sure so so as as i understand it that uh for example i read boston's book and a bunch of other reading material about this sort of general way of thinking about the world and i think the story goes something like this that we will at some point create computers that are smart enough that they can help design the next version of themselves which itself will be smarter than the previous version of themselves and eventually bootstrapped up to being smarter than us at which point we are essentially at the mercy of this sort of more powerful intellect which in principle uh we don't have any control over what its goals are and so if its goals are at all out of sync with our goals like the ex for example the continued existence of humanity we won't be able to stop it it'll be way more powerful than us and we will be toast so there's some i don't know very smart people who have signed on to that story and it's a it's a compelling story i once now i can really get myself in trouble i once wrote an op-ed about this specifically responding to some quotes from elon musk who has been you know on this very podcast uh more than once and well the e-e-a-i's summoning the demon that you get i think he said but then he came to providence rhode island which is where i live and said uh to the governors of all the states uh you know you're worried about entirely the wrong thing you need to be worried about ai you need to be very very worried about ai so uh and peop journalists kind of reacted to that and they wanted to get people's people's take and i was like okay my my my belief is that one of the things that makes elon musk so successful and so remarkable as an individual is that he believes in the power of ideas he believes that you can have you can if you know if you have a really good idea for getting into space you can get into space if you have a really good idea for a company or for how to change the way that people drive you just have to do it and and it can happen it's really natural to apply that same idea to ai you see these systems that are doing some pretty remarkable computational tricks uh demonstrations and then to take that idea and just push it all the way to the limit and think okay where does this go where is this going to take us next and if you're a deep believer in the power of ideas then it's really natural to believe that those ideas could be taken to the extreme and kill us so i think you know his strength is also his undoing because that doesn't mean it's true like it doesn't mean that that has to happen but it's natural for him to think that so another way to phrase the way he thinks and i find it very difficult to argue with that line of thinking uh so sam harris is another person from neuroscience perspective that things like that is saying well is there something fundamental in the physics of the universe that prevents this from eventually happening and this nebosh from things in the same way they're kind of zooming out yeah okay we humans now uh are existing in this like time scale of minutes and days and so our intuition is in this time scale of minutes hours and days but if you look at the span of human history is there any reason we you can't see this in in 100 years and like is there is there something fundamental about the laws of physics that prevent this and if it doesn't then it eventually will happen or will we will destroy ourselves in some other way it's very difficult i find to actually argue against that yeah me too and not sound like not sound like you're just like rolling your eyes uh i'm like i have like science fiction we don't have to think about it but even even worse than that which is like i don't know kids but like i gotta pick up my kids now like this okay i see there's more pressing shortcuts yeah there's more pressing short-term things that like uh stop over this existential crisis where much much shorter things like now especially this year there's cova so like any kind of discussion like that is like there's there's p you know there's pressing things uh today it's it's and then so the sam harris argument well like any day the exponential singularity can can occur it's very difficult to argue against i mean i don't know but part of his story is also he's he's not going to put a date on it it could be in a thousand years it could be in 100 years it could be in two years it's just that as long as we keep making this kind of progress it's ultimately has to become a concern i i kind of am on board with that but the thing that the the piece that i feel like is missing from that that way of extrapolating from the moment that we're in is that i believe that in the process of actually developing technology that can really get around in the world and really process and and and do things in the world in a sophisticated way we're going to learn a lot about what that means which that we don't know now because we don't know how to do this right now if you believe that you can just turn on a deep learning network and eventually give it enough compute and it'll eventually get there well sure that seems really scary because we won't we won't be in the loop at all we want we won't be helping to design or or target these kinds of systems but i don't i don't see that that feels like it is against the laws of physics because these systems need help right they need they need to surpass the the the difficulty the wall of complexity that happens in arranging something in the form that that will happen in yeah like i believe in evolution like i believe that the that that there's an argument right so there's another argument just to look at it from a different perspective that people say well i don't believe in evolution how could evolution it's it's sort of like a random set of parts assemble themselves into a 747 and that could just never happen yeah so it's like okay that's maybe hard to argue against but clearly 747s do get assembled they get assembled by us basically the idea being that there's a process by which we will get to the par the point of making technology that has that kind of awareness and in that process we're going to learn a lot about that process and we'll have more ability to control it or to shape it or to build it in our own image it's not something that is going to spring into existence like that 747 and we're just gonna have to contend with it completely unprepared it's very possible that in the context of the long arc of human history it will in fact spring into existence but that springing might take like if you look at nuclear weapons like even 20 years is a springing in in the context of human history and it's very possible just like with nuclear weapons that we could have i don't know what percentage you want to put at it but the the possibility could have knocked ourselves out yeah the possibility of human beings destroying themselves in the 20th century with nuclear weapons i don't know you can if you really think through it you could really put it close to like i don't know 30 40 percent given like the certain moments of crisis that happen so like i think one like fear in the shadows that's not being acknowledged is it's not so much the ai will run away is is that as it's running away we won't have enough time to uh think through how to stop it right fast takeoff or foom yeah i mean my much bigger concern i wonder what you think about it which is we won't know it's happening so i kind of that argument i think that there is an agi situation already happening with social media that our minds our collective intelligence of human civilization is already being controlled by an algorithm and like we're we're already super like the the level of a collective intelligence thanks to wikipedia people should donate to wikipedia to feed the agi man if we had a super intelligence that that was in line with wikipedia's values that it's a lot better than a lot of other things i can imagine i've i trust wikipedia more than i trust facebook or youtube as far as trying to do the right thing from a rational perspective yeah now that's not where you were going i understand that but it it it does strike me that there's sort of smarter and less smart ways of of exposing ourselves to each other on the internet yeah the interesting thing is that wikipedia and social media have very different forces you're right i mean wikipedia if if agi was wikipedia it'd be just like this cranky overly competent editor of uh articles uh you know there's there's something to that but the social media aspect is is is not so the vision of agis is as a separate system that's super intelligent that's super intelligent that's one key little thing i mean there's the paper clip argument that's super dumb but super powerful systems but with social media you have a relatively like algorithms we may talk about today very simple algorithms that when uh something charles talks a lot about which is interactive ai when they start like having at scale like tiny little interactions with human beings they can start controlling these human beings so a single algorithm can control the minds of human beings slowly to what we might not realize it could start wars it could start it can change the way we think about things it feels like in the long arc of history if i were to sort of zoom out from all the outrage and all the tension on social media that it's progressing us towards uh better and better things it feels like chaos and toxic and all that kind of stuff but it's chaos and toxic yeah but it feels like actually the chaos and toxic is similar to the kind of debates we had from the founding of this country you know there was a civil war that happened over that over that period and ultimately it was all about this tension of like something doesn't feel right about our implementation of the core values we hold as human beings and they're constantly struggling with this and that results in people calling each other uh like just just being shitty to each other on twitter but i ultimately the algorithm is managing all that and it feels like there's a possible future in which that algorithm controls us to into the direction of self-destruction whatever that looks like yeah so so all right i do believe in the power of social media to screw us up royally i do believe in the power of social media to benefit us too i do think that we're in a yeah it's sort of almost got dropped on top of us and now we're trying to as a culture figure out how to cope with it there's a sense in which i don't know there's there's some arguments that say that for example i guess college-age students now late college-age students now people who are in middle school when when social media started to really take off maybe maybe really damaged like me this may have really hurt their development in a way that we don't have all the implications of quite yet that's the generation who if and i hate to make it somebody else's responsibility but like they're the ones who can fix it they're the ones who can who can figure out how do we keep the good of this kind of technology without letting it eat us alive and if they're successful we move on to the next phase the next level of the game if they're not successful then yeah then we're going to wreck each other we're going to destroy society so you're going to in your old age sit on the porch and watch the world burn because the tick tock generation that uh i believe well so my this is my kids age right and that's certainly my daughter's age and she's very tapped in to social stuff but she's also she's trying to find that balance right of participating in it and then getting the positives of it but without letting it eat her alive um and i think sometimes she ventures hopes just to watch this sometimes i think she ventures a little too far and is in and is consumed by it and other times she gets a little distance um and if you know if there's enough people like her out there they're gonna they're gonna navigate this this choppy waters that's that's an interesting uh skill actually to develop i talked to my dad about it you know i've uh now somehow this podcast in particular but other reasons has received a little bit of attention and with that apparently in this world even though i don't shut up about love and i'm just all about kindness i i have now a little mini army of trolls oh it's kind of hilarious actually but it also doesn't feel good but it's a skill to learn to not look at that like to moderate actually how much you look at that the discussion i have with my dad is similar to uh it doesn't have to be about trolls it could be about checking email which is like if you're anticipating you know there's uh my dad runs a large institute at drexel university and there could be stressful like emails you're waiting like there's drama of some kind and so like there's a temptation to check the email if you send an email you cut it and that pulls you in into it doesn't feel good and it's a skill that he actually complains that he hasn't learned i mean he grew up without it so he hasn't learned the skill of how to shut off the internet and walk away and i think young people while they're also being quote-unquote damaged by like uh you know being bullied online all those stories which are very like horrific you basically can't escape your bullies these days when you're growing up but at the same time they're also learning that skill of how to be able to shut off uh the like disconnect with it be able to laugh at it not take it too seriously it's fascinating like we're all trying to figure this out just like you said it's been dropped on us and we're trying to figure it out yeah i think that's really interesting and i i guess i've become a believer in the human design which i feel like i don't completely understand like how do you make something as robust as us like we're so flawed in so many ways and yet and yet you know we dominate the planet and we do seem to manage to get ourselves out of scrapes eventually not necessarily the most elegant possible way but somehow we get we get to the next step and i don't know how i'd make a machine do that i i i generally speaking like if i train one of my reinforcement learning agents to play a video game and it works really hard on that first stage over and over and over again and it makes it through it succeeds on that first level and then the new level comes and it's just like okay i'm back to the drawing board and somehow humanity we keep leveling up and then somehow managing to put together the skills necessary to achieve success some semblance of success in that next level too and you know i hope we can keep doing that you mentioned reinforcement learning so you've have uh a couple years in the field no quite you know quite a few quite a long career in artificial intelligence broadly but reinforcement learning specifically can you maybe give a hint about your sense of the history of the field and in some ways has changed with the advent of deep learning but has a long roots like how is it weaved in and out of your own life how have you seen the community change or maybe the ideas that it's playing with change i've had the privilege the pleasure of being of having almost a front row seat to a lot of this stuff and it's been really really fun and interesting so uh when i was in college in the 80s early 80s uh the neural net thing was starting to happen and i was taking a lot of psychology classes a lot of computer science classes as a college student and i thought you know something that can play tic-tac-toe and just like learn to get better at it that ought to be a really easy thing so i spent almost almost all of my what would have been vacations during college like hacking on my home computer trying to teach it how to play tic-tac-toe and programming language basic oh yeah that's that's i was i that's my first language that's my native language is that when you first fell in love with computer science just like programming basic on that uh what was the computer do you remember i had i had a trs-80 model one before they were called model ones because there was nothing else uh i got my computer in 1979 uh instead so i was i was i would have been bar mitzvahed but instead of having a big party that my parents threw on my behalf they just got me a computer because that's what i really really really wanted i saw him in the in the in the mall in radio shack and i thought what how are they doing that i would try to stump them i would give them math problems like one plus and then in parentheses two plus one yeah and i would always get it right i'm like how do you know so much message like i've had to go to algebra class for the last few years to learn this stuff and you just seem to know so i was i was i was smitten and i got a computer and i think ages 13 to 15 i have no memory of those years i think i just was in my room with the computer listening to billy joel communing possibly listening to the radio listening to billy joel that was the one album i had uh on vinyl at that time and um and then i got it on cassette tape and that was really helpful because then i could play it i didn't have to go down to my parents wi-fi or hi-fi sorry uh and at age 15 i remember kind of walking out and like okay i'm ready to talk to people again like i've learned what i need to learn here and um so yeah so so that was that was my home computer and so i went to college and i was like oh i'm totally going to study computer science i opted the college i chose specifically had a computer science major the one that i really wanted the college i really wanted to go to didn't so bye-bye to them which college did you go through so i went to yale uh princeton would have been way more convenient and it was just beautiful campus and it was close enough to home and i was really excited about princeton and i visited i said so computer science major like well we have computer engineering i'm like oh i don't like that word engineering i like if you're science i really i want to do like you're saying hardware and software they're like yeah like i just want to do software i i couldn't care less about hardware you grew up in philadelphia i grew up outside philly yeah yeah okay uh so the you know local schools were like penn and drexel and uh temple like everyone in my family went to temple at least at one point in their lives except for me so yeah philly philly family yale had a computer science department and that's when you it's kind of interesting you said 80s and you're all that works that's when you know that which is a hot new thing or a hot thing period uh so what is that in college when you first learned about neural networks yeah yeah was she learned like it was in a psychology class not in a cs wow yeah was it psychology or cognitive science or like do you remember like what context it was yeah yeah yeah so so i was a i've always been a bit of a cognitive psychology groupie so like i studied computer science but i like i like to hang around where the cognitive scientists are because i don't know brains man they're like they're wacky cool and they have a bigger picture view of things they're a little less engineery i would say they're more they're more interested in the nature of cognition and intelligence and perception it's called like the vision system work they're asking always bigger questions now with the deep learning community there i think more there's a lot of intersections but i do find in that the neuroscience folks actually and uh cognitive psychology cognitive science folks are starting to learn how to program how to use your own artificial neural networks and they are actually approaching problems in like totally new interesting ways it's fun to watch that grad students from those departments like approach the problem of machine learning right they come in with a different perspective yeah they don't care about like your imagine that data set or whatever they they want like to understand the the like the basic mechanisms at the at the neuronal level and the functional level of intelligence it's kind of it's kind of cool to see them work but yeah okay so you always you're always a group you have cognitive psychology yeah yeah and so uh so it was in a class by richard garrick he was kind of my my favorite uh psych professor in college and i took uh like three different classes with him and yeah so that we they were talking specifically the class i think was kind of a there was a big paper that was written by stephen pinker and uh prince i don't i'm blanking on prince's first name but prince and pinker and prince they wrote kind of a they were at that time kind of like ah i'm blanking on the names of the current people um the cognitive scientists who are complaining a lot about deep networks oh uh gary gary marcus sorry marcus and who else i mean there's a few but gary gary's the most feisty sure gary's very feisty and with this with his co-author they they you know they're kind of doing these kind of takedowns where they say okay well yeah it does all these amazing amazing things but here's a shortcoming here's a shortcoming here's your shortcoming and so the pinker prince paper is kind of like the that generation's version of marcus and davis right where they're they're trained as cognitive scientists but they're looking skeptically at the results in the in the artificial intelligence neural net kind of world and saying yeah it can do this and this and this but like it can't do that and it can't do that and it can't do that maybe in principle or maybe just in practice at this point but but the fact of the matter is you're you've narrowed your focus too far to be impressed you know you're impressed with the things within that circle but you need to broaden that circle a little bit you need to look at a wider set of problems and so um so we have so i was in this seminar in college that was basically a close reading of the pinker prince paper which was like really thick there was a lot going on in there and um and and it talked about the reinforcement learning idea a little bit i'm like oh that sounds really cool because behavior is what is really interesting to me about psychology anyway so making programs that i mean programs are things that behave people are things that behave like i want to make learning that learns to behave in which way was reinforcement learning presented is this uh talking about human and animal behavior or are we talking about actual mathematical constructs ah that's right so that's a good question right so this is i think it wasn't actually talked about as behavior in the paper that i was reading i think that it just talked about learning and to me learning is about learning to behave but really neural nets at that point were about learning like supervised learning so learning to produce outputs from inputs so i kind of tried to invent reinforcement learning i uh when i graduated i joined a research group at bellcore which had spun out of bell abs recently at that time because of the divestiture of the of long distance and local phone service in the 1980s 1984 and i was in a group uh with dave ackley who was the first author of the boltzmann machine paper so the very first neural net paper that could handle xor right so xor sort of killed neural nets the very first the zero with the first winter yeah um the the perceptron's paper and hinton along with his student dave ackley and and i think there was other authors as well showed that no no with both machines we can actually learn non-linear concepts and so everything's back on the table again and that kind of started that second wave of neural networks so dave ackley was he became my mentor at bellcore and we talked a lot about learning and life and computation and how all these things fit together now dave and i have a podcast together so um so i get to kind of enjoy that sort of his his perspective uh once again even even all these years later and so i said so i said i was really interested in learning but in the concept of behavior and he's like oh well that's reinforcement learning here and he gave me rich sutton's 1984 td paper so i read that paper i honestly didn't get all of it but i got the idea i got that they were using that he was using ideas that i was familiar with in the context of neural nets and and like sort of backprop uh but with this idea of making predictions over time i'm like this is so interesting but i don't really get all the details i said to dave and dave said oh well why don't we have him come and give a talk and i was like wait what you can do that like these are real people i thought they were just words i thought it was just like ideas that somehow magically seeped into paper he's like no i i i know rich like we'll just have him come down and and he'll give a talk and so i was you know my mind was blown and uh so rich came and he gave a talk at bellcore and he talked about what he was super excited which was they had just figured out at the time uh q learning so uh watkins had visited the rich sutton's lab at umass or it's andy barto's lab that rich was a part of and um he was really excited about this because it resolved a whole bunch of problems that he didn't know how to resolve in the in the earlier paper and so uh for people who don't know td temporal difference these are all just algorithms for reinforcement learning right and td separate difference in particular is about making predictions over time and you can try to use it for making decisions right because if you can predict how good a future action and action outcomes will be in the future you can choose one that has better and or but the theory didn't really support changing your behavior like the predictions had to be of a consistent process if you really wanted it to work and one of the things that was really cool about q-learning algorithm for reinforcement learning is it was off policy which meant that you could actually be learning about the environment and what the value of different actions would be while actually figuring out how to behave optimally yeah so that was a revelation yeah and the proof of that is kind of interesting i mean that's really surprising to me when i first read that and then enriched rich sutton's book on the matter it's it's kind of beautiful that a single equation can capture an equation one line of code and like you can learn anything yeah like enough time so equation and code you're right like you can the code that you can arguably at least if you like squint your eyes can say this is all of intelligence is that you can implement that in a single wall i think i started with lisp which is uh shout out to lisp uh like a single line of code key piece of code maybe a couple that you could do that it's kind of magical it's uh feels too good to be true well and it sort of is yeah it's kind of kind of it seems to require an awful lot of extra stuff supporting it but yeah but nonetheless the ideas the the idea is really good and as far as we know it is it is a very reasonable way of trying to create adaptive behavior behavior that gets better at something over time did you find the idea of optimal uh at all compelling that you could prove that it's optimal so like one part of computer science that it makes people feel warm and fuzzy inside is when you can prove something like that a sorting algorithm worst case runs and and log n and it makes everybody feel so good even though in reality it doesn't really matter what the worst case is what matters is like does this thing actually work in practice on this particular actual set of data that i that i enjoy did you so here's that here's a place where i have maybe a strong opinion uh-oh which is like you're right of course but no no like so so the what makes worst case so great right if you have a worst case analysis so great is that you get modularity you can take that thing and plug it into another thing and still have some understanding of what's going to happen when you click them together right if it just works well in practice in other words with respect to some distribution that you care about when you go plug it into another thing that distribution can shift it can change and your thing may not work well anymore and you want it to and you wish it does and you hope that it will but it might not and then ah so you're so so you're saying you don't like machine learning but we have some positive theoretical results for these things you know you can come back at me with yeah but they're really weak and yeah they're really weak and and you can even say that you know sorting algorithms like if you do the optimal sorting algorithm it's not really the one that you want and that might be true as well but but it is the modularity is a really powerful statement really as an engineer you can then assemble different things you can count on them to be i mean it's interesting it's it's a balance like with everything else in life you don't want to get too obsessed i mean this is what computer scientists do which they potentially get obsessed they over optimize things or they start by optimizing them they over optimize yeah so it
Resume
Categories