Dopamine System, Craving & Pursuit Explained | Dr. Andrew Huberman
00:00:00.000 | [silence]
00:00:02.440 | So let's think about dopamine peaks and baselines.
00:00:05.920 | And let's remember that for every peak, there's a trough.
00:00:09.760 | What do I mean by that?
00:00:10.600 | Well, when you have a wave,
00:00:12.600 | you also have the bottom of the wave.
00:00:14.720 | When you have a mountain, you have the bottom of the mountain.
00:00:18.840 | When we think about dopamine peaks and dopamine baselines,
00:00:22.840 | we have to include that trough because that trough,
00:00:26.560 | that is the level of dopamine below baseline,
00:00:31.320 | really dictates whether or not you are going to feel
00:00:34.040 | motivated to pursue something or not.
00:00:36.460 | So I'm going to give you a visual in your mind.
00:00:38.200 | The visual in your mind is an increase in dopamine
00:00:41.620 | that's triggered by your desire for something.
00:00:45.060 | And really it could be your desire for anything.
00:00:47.040 | If you're hungry and you're thinking about,
00:00:48.960 | I really want a sandwich.
00:00:50.520 | I really want a, let's think,
00:00:51.880 | what sandwich would I want right now?
00:00:53.120 | A really nice roast beef sandwich on sourdough
00:00:55.640 | with a slice of Swiss, tomatoes, slice of pickle.
00:00:58.400 | Here I'm describing the sandwich that I would want.
00:01:00.460 | So if you're hungry and you're thinking about that,
00:01:03.160 | dopamine starts rising.
00:01:05.480 | This is crucially important to understand.
00:01:07.640 | Dopamine is not just released when we get the reward,
00:01:11.180 | when we get the thing that we're pursuing.
00:01:12.680 | Dopamine is released in anticipation of what we want.
00:01:17.300 | That increase in dopamine is by no happenstance,
00:01:22.960 | no mistake, relates also to our propensity
00:01:27.040 | and desire to move.
00:01:28.320 | Remember earlier I told you there's a separate circuit
00:01:30.260 | of dopamine that triggers movement
00:01:33.040 | and that when it's depleted is causing things
00:01:36.180 | like deficits in movement related to Parkinson's
00:01:38.520 | or other movement disorders.
00:01:40.000 | Well, that's not pure coincidence.
00:01:42.520 | That's because desire and the need to move
00:01:45.320 | in order to pursue and reach goals
00:01:47.600 | are one in the same process.
00:01:50.280 | So if I desire a sandwich or I desire a cup of coffee
00:01:54.000 | or I desire some water when I'm thirsty,
00:01:56.080 | there's an increase in dopamine
00:01:57.680 | that we could call a little mini peak in dopamine.
00:02:00.800 | But then here's the key thing.
00:02:02.520 | Very soon after I realized my desire for something,
00:02:06.420 | that peak that was caused by the desire
00:02:10.640 | comes down and drops below baseline,
00:02:13.800 | below the level of dopamine that it was prior
00:02:16.960 | to even thinking about the sandwich or the coffee
00:02:19.000 | or the glass of water.
00:02:20.200 | And it's that drop below baseline
00:02:23.680 | that triggers my desire to go out and find that sandwich,
00:02:27.800 | that coffee, that water, or that blank,
00:02:30.840 | insert whatever it is that you happen to desire,
00:02:33.000 | action or substance of any kind or person, et cetera.
00:02:37.240 | So that drop below baseline is fundamental
00:02:40.360 | to the whole process.
00:02:41.280 | And that drop below baseline was triggered
00:02:43.800 | by the preceding peak.
00:02:45.440 | So let's say that I desire a sandwich,
00:02:47.240 | there's an increase in dopamine.
00:02:48.800 | Then very quickly, it comes down below baseline
00:02:51.600 | just a little bit.
00:02:52.680 | Now I'm in pursuit of the sandwich.
00:02:53.880 | I'm looking for where I can get that sandwich.
00:02:55.960 | I can order it, perhaps to be delivered.
00:02:57.880 | I can go out and find it.
00:02:59.120 | Now is the stage in which I have to think about
00:03:02.760 | what are the different stimuli,
00:03:05.000 | that is the things in my environment
00:03:06.440 | that signal whether or not I'm likely
00:03:08.100 | to get that sandwich or not.
00:03:09.920 | And so for instance, if I were to go into my phone
00:03:12.000 | and order food on an app or walk down the street
00:03:14.600 | and see the sign for a deli,
00:03:17.040 | that's a cue that I'm likely to relieve that drop
00:03:22.040 | in dopamine and get not just back to baseline,
00:03:25.080 | but that I'll get a peak in dopamine.
00:03:26.840 | And indeed that's what happens.
00:03:28.080 | If I find that deli, I go into the deli,
00:03:31.440 | they're open, they're making the sandwich that I want,
00:03:33.360 | they make my sandwich and great, I get that sandwich.
00:03:36.000 | And that sandwich will have some degree
00:03:37.620 | of inherent reward to it.
00:03:40.120 | Some degree of my liking it or not liking it.
00:03:43.400 | So let's say I like it.
00:03:44.400 | It's not the best sandwich I've ever had,
00:03:45.840 | but all I'm doing is comparing my desire for that sandwich
00:03:49.520 | to the sandwich that I actually got and ate.
00:03:52.080 | And chances are, it's going to relieve that craving,
00:03:55.600 | meaning it will take that dopamine
00:03:57.600 | that had fallen below baseline, up, up, back to baseline.
00:04:00.760 | And if I like the sandwich,
00:04:02.200 | it's going to indeed increase that dopamine,
00:04:05.060 | again, to another peak.
00:04:06.480 | Now, if I love the sandwich,
00:04:09.160 | like it's the most delicious thing
00:04:10.480 | that I've ever tasted in my entire life,
00:04:12.340 | well then I'll get a big peak in dopamine
00:04:15.340 | when I consume that reward.
00:04:17.560 | However, chances are the sandwich is more or less
00:04:20.160 | as I expect it to be, which is pretty good.
00:04:22.280 | I'll eat it and I'm fine.
00:04:23.760 | What do I mean by fine?
00:04:24.960 | Well, there's a concept called reward prediction error.
00:04:27.400 | Reward prediction error says that the dopamine
00:04:31.080 | that it has experienced, that is,
00:04:32.920 | that's released from the VTA and nucleus accumbens,
00:04:35.660 | is going to be of a certain value.
00:04:38.980 | And that value is going to be compared
00:04:41.120 | to the desire and expectation
00:04:42.860 | of what I thought I was going to get.
00:04:44.940 | So if you take what you actually got
00:04:46.640 | minus what you expected, that's reward prediction error.
00:04:49.960 | So if the sandwich is basically what I expected to get,
00:04:52.600 | fine, dopamine comes down basically to a baseline level
00:04:56.160 | that's pretty standard for me
00:04:57.240 | and is basically the baseline level I had
00:04:59.040 | before I ever thought about the sandwich at all.
00:05:01.840 | If the sandwich completely surprises me
00:05:03.980 | and is completely amazing, just an amazing sandwich,
00:05:07.280 | well then, the level of dopamine that I experience
00:05:10.040 | when I consume that sandwich is going to be even greater
00:05:13.320 | and it's going to be that minus what I expected.
00:05:16.720 | So there, it's a bigger reward prediction error
00:05:19.520 | in the direction of higher peak by consuming the sandwich.
00:05:24.140 | And then of course, there's the other possibility,
00:05:25.960 | which is the deli's closed
00:05:28.360 | or the sandwich they make me is lousy
00:05:30.160 | or it doesn't taste good or something happened
00:05:33.240 | in the consuming of that sandwich
00:05:34.800 | that just makes it a bad experience.
00:05:36.900 | In which case, if we take that reward experienced
00:05:39.600 | minus reward predicted from the initial craving,
00:05:44.520 | well then it's going to be less than what I expected
00:05:47.080 | and therefore the baseline drops below
00:05:49.920 | where it was prior to even desiring the sandwich.
00:05:53.680 | Okay, so all of this might seem a little bit complicated,
00:05:55.720 | but it's all very simple.
00:05:57.160 | Desire for things increases dopamine,
00:05:59.720 | but then our level of dopamine drops below baseline
00:06:02.760 | and it's that drop below baseline
00:06:04.800 | that triggers the motivation
00:06:06.520 | to bring that dopamine level back up
00:06:09.200 | by going and pursuing the thing
00:06:11.200 | that you wanted in the first place.
00:06:13.880 | Now, of course, as this is happening,
00:06:15.840 | you're not conscious of your dopamine levels.
00:06:17.840 | You experience this as context-dependent craving and pursuit.
00:06:22.160 | Because remember, the prefrontal cortex
00:06:23.540 | is involved in context setting and craving and pursuit
00:06:27.200 | because it relates to action and movement,
00:06:29.620 | which is one of the general features of the dopamine system.
00:06:33.200 | So you can start to see
00:06:34.080 | how this is a beautifully designed system.
00:06:36.200 | And you can also see how it's a perfect system
00:06:39.140 | for desire and pursuit of anything, not just sandwiches,
00:06:43.700 | as I'm giving you in this somewhat trivial,
00:06:45.600 | but everyday and therefore applicable example.
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