9 ms·

Rat Park

258 points by happyscrappy 12y ago

voxic11 12y ago
Or, in comic format http://www.stuartmcmillen.com/comics_en/rat-park/ http://www.stuartmcmillen.com/comics_en/rat-park/
- Kronopath 12y ago
  What an excellent, approachable summary of the results of the experiment.
- 542458 12y ago
  Holy cow, what a terrible website. Hijacks the back button, scrolling is so over-sensitive as to be useless, the left and right perform in non-intuitive ways, and the animations all have a delay before they start.
  - bradbeattie 12y ago
    Further, scroll a few pages using your scrollwheel, then press the right key. You'd expect to continue to the right, but instead are scrolled all the way back to the left to page #2. Eesh.
mamer 12y ago
I lived in an apartment where 6 out of 8 apartments were occupied by alcoholics or drug addicts. Nearly every block on that street was the same. This was Glasgow, and the drug of choice was heroin, although everyone also smoked as much marijuana as they could afford. These people's lives weren't particularly shit on a day-by-day basis, but they had nothing but misery on the horizon. If they had kids they would lose them, they would never work, never be praised. They'd never see the world. Most of them hadn't been outside Glasgow for years, if not the whole of their lives. They would probably never go to the beach or on even the shittest package holiday. Those who were obviously junkies (struggling to walk, sunken faces and destroyed skin) were basically seen as an underclass by everyone from their peers, to the rest of the population and the police. But there were people living in the same street, in the same apartments, with far less money, working shitty jobs, who weren't even open to taking drugs. The structure of this area wasn't bad at all - it could have been Rat Park, if it wasn't filled with drug-addicted rats who just pissed in the common areas and threw their rotting food out of the window. I don't have any great insight here - but I think there's more to it than environment as suggested by this study. There are people all around the world who live in far worse conditions and who aren't turning to substances, even when they are available. My feeling is that rats living in cages, who can see rats living in Rat Park would be more likely to seek addiction. And perhaps even more so if they see other rats being moved from cages to Rat Park, but not them. I don't know if rats could understand this concept though, which might be why they aren't all living in Afghanistan's poppy fields.
- Retric 12y ago
  It's important to note that people’s environment is heavily influenced by their social circle. Day to Day a poor person that has a strong social circle and some free time to sit around and play cards can be happier than say an elderly widower who might have plenty of resources but few friends or family left alive. IMO, Rat Park would have been far more interesting if they had presented rats with identical environments but the difference being social isolation not just living in a tiny cage.
- njharman 12y ago
  I think the basic question are "loosers" made or born. That is, does someone with a bright future try drugs and then spiral down the shitter as is commonly portrayed in media and government anti-drug propaganda. Or, does someone who is a fuck up, failure at life, find themselves in the shitter and start using drugs to avoid their looser life. I'm sure, as in most things, the reality is a gradient between those extremes. But it sure seems majority only believe / see first extreme.
- api 12y ago
  I suspect it's not all environment, but this study argues that environment (and social realities, etc.) are a significant component -- it's not just a matter of chemical dependence only.
- spb 12y ago
  So, basically, you lived in Trainspotting?
- Brakenshire 12y ago
  > I don't have any great insight here - but I think there's more to it than environment as suggested by this study. There are people all around the world who live in far worse conditions and who aren't turning to substances, even when they are available. My feeling is that rats living in cages, who can see rats living in Rat Park would be more likely to seek addiction. And perhaps even more so if they see other rats being moved from cages to Rat Park, but not them. To a certain degree it comes down to a semantic argument about how you define environment. * Just the structural physical environment - nice benches, and trees, flats that are a decent size, and don't have mould on the walls, etc * this plus the consequences of other people on the physical environment - needles left in parks, shouting in the corridors, people pissing in the lift * this plus the immediate social environment - you are treated badly because you look like a drug addict * this plus the cumulative internalized values that you have picked up from your social environment throughout your lifetime - other people living successful, prosperous lives around you, or in mass media, and you falling short of your expectations Rats don't necessarily have the latter two, at least I don't think they have a social stigma for drug addiction! For humans, the parallels are inevitably to some degree limited, because you can't just take someone out of their own mind, and put them somewhere where they feel good about themselves, although you can try, and will succeed with many.
nemothekid 12y ago
Reminds me of reddit comment I once read of someone's experience with heroin - http://www.reddit.com/r/Drugs/comments/1rhn38/heroin_users_of_rdrugs_are_you_addicts/cdnfuxe http://www.reddit.com/r/Drugs/comments/1rhn38/heroin_users_o...
- api 12y ago
  I knew someone once who'd used heroin for a while and gave it up and he told a similar story. He said it "makes the pain go away," and I asked what he meant and he just said "all of it" and smiled. He said I'm in horrible, horrible pain and have no idea because I'd never tried heroin before. :O Immediately made me think of this great old sci-fi story: http://bestsciencefictionstories.com/2009/05/17/desertion-by-clifford-d-simak/ http://bestsciencefictionstories.com/2009/05/17/desertion-by...
  - chrisBob 12y ago
    My wife said something similar about morphine: "Did you know your hand hurts really bad while you are just standing there right now? You have no idea until you have morphine and it gets instantly better."
    - SapphireSun 12y ago
      That's really interesting. I imagine nociceptors have a baseline firing rate but your brain tunes it out because it's just noise. If you switch that off, the current filter system would get whacked out of balance, you'd feel awesome, but when it switches on again, baseline firing would be a salient input for a bit and you might notice it? Of course, long term up/down regulation of various receptors occurs too, but I've never heard of this particular effect before though it sounds plausible to me.
      - api 12y ago
        I wondered a while back if (theoretically) taking some kind of non-harmful but pain stimulating compound might not make you feel awesome the rest of the time, and might even be good for you by recalibrating your inflammatory response and such.
raldi 12y ago
He's lucky he didn't do this experiment in today's climate; it would've been the new "shrimp treadmills".
b_emery 12y ago
From near the bottom: "Some further studies failed to reproduce the original experiment's results, but in at least one of these studies[12] both caged and "park" rats showed a decreased preference for morphine, suggesting a genetic difference" Still, it's an intriguing result. The reviewer comments from science and nature would make interesting reading - too bad they are not public.
- kbenson 12y ago
  But also, from the immediately preceding paragraph: "Several later studies did appear to confirm its findings — for example, Bozarth, Murray and Wise in 1989, also published in Pharmacology, Biochemistry and Behavior — but nothing came of those either." That paints a confusing picture, so without looking at the specifics of the later studies for possible differences, I think it's hard to come to a conclusion.
  - bjourne 12y ago
    Wikipedia isn't so good when it comes to drug related topics. Or rather, it is atrocious since the linked study (http://wings.buffalo.edu/aru/HOUSING.html http://wings.buffalo.edu/aru/HOUSING.html) arrives at the completely opposite result Wikipedia claims. It's an interesting read because it also discusses why setting up a study to fairly measure voluntary drug intake among groups of mice is very hard.
    - spb 12y ago
      > it is atrocious since the linked study arrives at the completely opposite result Wikipedia claims. Wikipedia allows public editing. Did you amend the incorrect claim?
    - kbenson 12y ago
      After reading portions of that study, I find it hard to make meaningful comparisons across them. The cited source's two conditions seem to be fairly close in many respects IMHO: "The first group was housed in individual stainless steel cages (18 x 25 x 18 cm) that prevented tactile and visual contact among the rats." "The second condition consisted of rats housed in groups of 10 in a large stainless steel cage (45 x 101 x 39 cm) that permitted social contact; these rats displayed normal play behavior, dominance struggles, and social grooming." Okay, one rat in 450 cm^2 vs 10 rats in 4545 cm^2, both in steel cages. Compared to Rat Park, which was 8.8m^2 (close to twice the size), and was specifically not a steel cage[1]. Then again, I doubt this study was done specifically to confirm or refute the earlier experiment, but to test further hypotheses in the same area. 1: http://www.brucekalexander.com/articles-speeches/rat-park/148-addiction-the-view-from-rat-park http://www.brucekalexander.com/articles-speeches/rat-park/14...
bjourne 12y ago
I'm just gonna be lazy and link to what I wrote the last time the Rat Park page came up on HN: https://news.ycombinator.com/item?id=7743089 https://news.ycombinator.com/item?id=7743089 It comes up a lot, maybe because the result is kind of positive and aligns well with HN's crowds drug liberal views? The RP experiment wrt morphine addiction in mice has not been replicated. Also, afaik, Bruce Alexander had a hypothesis about drug addiction, designed an experiment to prove his hypothesis. Performed the experiment, measured the results and found that they confirmed his hypothesis. It's not a good way to do research. The results of the Stanford Prison Experiment and the Milgram experiments should be discredited for the same reason. Because their results were tainted by their designer. Extraordinary claims requires extraordinary proofs. That mice wouldn't become addicted to morphine is most certainly an extraordinary claim.
- shutupalready 12y ago
  > had a hypothesis about drug addiction, designed an experiment to prove his hypothesis. Performed the experiment, measured the results That's the very definition of the Scientific Method, so I don't understand what problem you're pointing out: "The overall process of the scientific method involves making conjectures ( hypotheses), deriving predictions from them as logical consequences, and then carrying out experiments based on those predictions." -- from http://en.wikipedia.org/wiki/Scientific_method http://en.wikipedia.org/wiki/Scientific_method (That the experiment has not been replicated as you claim could be a bad sign, but that's a separate matter.)
  - nemo1618 12y ago
    The issue is that there's a conflict of interest when the same person who proposed the hypothesis is the same person attempting to prove that hypothesis. This sort of bias is why meta-analysis exists.
  - spb 12y ago
    The problem is designing an experiment to confirm the hypothesis rather than to test it.
cthalupa 12y ago
Diacetylmorphine is still used in several European countries as a front line analgesic. Other forms of morphine are widely used for pain relief on a prescribed basis all over. If it is as simple as using morphine addicts you to morphine, why are no much wider swathes of the population addicted to it? I don't know that it's purely environment, but there's plenty of evidence out there that seems to suggest it's more than simply chemical dependency.
- vilhelm_s 12y ago
  Really? Which countries are those? My impression was that basically the only country that uses heroin for pain relief is the UK, and even there it is basically only used in cases where addition is not an issue, e.g. terminal cancer patients.
  - cthalupa 12y ago
    I might have been mistaken on several countries - I can only find sources for it's use in the UK But it is used by first responders as well: http://www.sjtrem.com/content/22/S1/P15 http://www.sjtrem.com/content/22/S1/P15 A decent amount of air ambulances polled use diamorphine. I'm pretty sure (but unfortunately having difficulty sourcing) regular ambulances have it available as well. It's widely used as palliative care in the UK as well, as you pointed out - but it might be worth noting that's not it's sole use, and palliative care doesn't always mean they're going to be dying soon enough that addiction wouldn't be a harmful issue to deal with.
O____________O 12y ago
This was brought up by Johann Hari on the Bill Maher show last week: https://www.youtube.com/watch?v=PxmvFRtYuYQ https://www.youtube.com/watch?v=PxmvFRtYuYQ (I heard that discussion discussed on the Adam Carolla Show from the 10th. I'm guessing it's a hot topic at the moment due to Hari promoting, I think, a book)
geographomics 12y ago
Puts me in mind of a study a few years back where they had socially housed monkeys self-administer cocaine [1]. Like all primates, each group of monkeys ended up with a dominance hierarchy. The most dominant had a relatively nice life compared with the subordinates: more grooming from others, more play, more attention in general. It turned out that the subordinate monkeys were much more susceptible to the temptations of cocaine. In contrast, the dominant ones were able to resist its allure a lot more effectively. The researchers also looked at the neurobiology of the monkeys. Before being socially housed, they were kept in individual cages for a couple of years. They looked at the main pleasure centre of the brain and measured the level of dopamine receptors (of the D2 type) present there. These receptors are directly stimulated by naturally occurring rewards like social activity, food, sex, and so on - but also stimulant drugs like cocaine. All the monkeys had pretty much the same D2 receptor level when they were cooped up in single cages, with little variation. But when they were socially housed, the D2 levels of the dominant monkeys rose significantly higher; this too was associated with their lessened vulnerability to cocaine. So it seemed that social environment can have quite the effect on the neurobiology of one's reward pathway, and potential for drug abuse (as the Rat Park experiment suggested). On reward pathways - in human stimulant addicts you also see lower D2 receptor levels than in non-addicts [2], although this is lacking a comparative reading from before they were addicted, so we don't know if that's near the state they were in when they started abusing the drug. Having said that, in non-addicts there is a natural variation in D2 receptor levels, and those with less D2 enjoy stimulants a lot more [3], just like the subordinate, lower D2 receptor monkeys. Unlike Rat Park, however, all the above is based on stimulants, which directly affect the aforementioned receptors. Whereas morphine takes a more indirect route, with different receptor types, so it's not quite comparable. Still, interesting to think about how much we may be slaves to our neurobiology, and our social surroundings. [1] doi:10.1038/nn798 [2] doi:10.1177/026988119901300406 [3] doi:10.1176/ajp.156.9.1440
MrJagil 12y ago
I would suggest this submission from a few days ago, to anyone interested in the subject: https://news.ycombinator.com/item?id=9029301 https://news.ycombinator.com/item?id=9029301

Rat Park

258 points by happyscrappy 12y ago

voxic11 12y ago

Or, in comic format http://www.stuartmcmillen.com/comics_en/rat-park/ http://www.stuartmcmillen.com/comics_en/rat-park/

Kronopath 12y ago
What an excellent, approachable summary of the results of the experiment.
542458 12y ago
Holy cow, what a terrible website. Hijacks the back button, scrolling is so over-sensitive as to be useless, the left and right perform in non-intuitive ways, and the animations all have a delay before they start.
- bradbeattie 12y ago
  Further, scroll a few pages using your scrollwheel, then press the right key. You'd expect to continue to the right, but instead are scrolled all the way back to the left to page #2. Eesh.

mamer 12y ago

I lived in an apartment where 6 out of 8 apartments were occupied by alcoholics or drug addicts. Nearly every block on that street was the same. This was Glasgow, and the drug of choice was heroin, although everyone also smoked as much marijuana as they could afford. These people's lives weren't particularly shit on a day-by-day basis, but they had nothing but misery on the horizon. If they had kids they would lose them, they would never work, never be praised. They'd never see the world. Most of them hadn't been outside Glasgow for years, if not the whole of their lives. They would probably never go to the beach or on even the shittest package holiday. Those who were obviously junkies (struggling to walk, sunken faces and destroyed skin) were basically seen as an underclass by everyone from their peers, to the rest of the population and the police. But there were people living in the same street, in the same apartments, with far less money, working shitty jobs, who weren't even open to taking drugs. The structure of this area wasn't bad at all - it could have been Rat Park, if it wasn't filled with drug-addicted rats who just pissed in the common areas and threw their rotting food out of the window. I don't have any great insight here - but I think there's more to it than environment as suggested by this study. There are people all around the world who live in far worse conditions and who aren't turning to substances, even when they are available. My feeling is that rats living in cages, who can see rats living in Rat Park would be more likely to seek addiction. And perhaps even more so if they see other rats being moved from cages to Rat Park, but not them. I don't know if rats could understand this concept though, which might be why they aren't all living in Afghanistan's poppy fields.

Retric 12y ago
It's important to note that people’s environment is heavily influenced by their social circle. Day to Day a poor person that has a strong social circle and some free time to sit around and play cards can be happier than say an elderly widower who might have plenty of resources but few friends or family left alive. IMO, Rat Park would have been far more interesting if they had presented rats with identical environments but the difference being social isolation not just living in a tiny cage.
njharman 12y ago
I think the basic question are "loosers" made or born. That is, does someone with a bright future try drugs and then spiral down the shitter as is commonly portrayed in media and government anti-drug propaganda. Or, does someone who is a fuck up, failure at life, find themselves in the shitter and start using drugs to avoid their looser life. I'm sure, as in most things, the reality is a gradient between those extremes. But it sure seems majority only believe / see first extreme.
api 12y ago
I suspect it's not all environment, but this study argues that environment (and social realities, etc.) are a significant component -- it's not just a matter of chemical dependence only.
spb 12y ago
So, basically, you lived in Trainspotting?
Brakenshire 12y ago
> I don't have any great insight here - but I think there's more to it than environment as suggested by this study. There are people all around the world who live in far worse conditions and who aren't turning to substances, even when they are available. My feeling is that rats living in cages, who can see rats living in Rat Park would be more likely to seek addiction. And perhaps even more so if they see other rats being moved from cages to Rat Park, but not them. To a certain degree it comes down to a semantic argument about how you define environment. * Just the structural physical environment - nice benches, and trees, flats that are a decent size, and don't have mould on the walls, etc * this plus the consequences of other people on the physical environment - needles left in parks, shouting in the corridors, people pissing in the lift * this plus the immediate social environment - you are treated badly because you look like a drug addict * this plus the cumulative internalized values that you have picked up from your social environment throughout your lifetime - other people living successful, prosperous lives around you, or in mass media, and you falling short of your expectations Rats don't necessarily have the latter two, at least I don't think they have a social stigma for drug addiction! For humans, the parallels are inevitably to some degree limited, because you can't just take someone out of their own mind, and put them somewhere where they feel good about themselves, although you can try, and will succeed with many.

nemothekid 12y ago

Reminds me of reddit comment I once read of someone's experience with heroin - http://www.reddit.com/r/Drugs/comments/1rhn38/heroin_users_of_rdrugs_are_you_addicts/cdnfuxe http://www.reddit.com/r/Drugs/comments/1rhn38/heroin_users_o...

api 12y ago
I knew someone once who'd used heroin for a while and gave it up and he told a similar story. He said it "makes the pain go away," and I asked what he meant and he just said "all of it" and smiled. He said I'm in horrible, horrible pain and have no idea because I'd never tried heroin before. :O Immediately made me think of this great old sci-fi story: http://bestsciencefictionstories.com/2009/05/17/desertion-by-clifford-d-simak/ http://bestsciencefictionstories.com/2009/05/17/desertion-by...
- chrisBob 12y ago
  My wife said something similar about morphine: "Did you know your hand hurts really bad while you are just standing there right now? You have no idea until you have morphine and it gets instantly better."
  - SapphireSun 12y ago
    That's really interesting. I imagine nociceptors have a baseline firing rate but your brain tunes it out because it's just noise. If you switch that off, the current filter system would get whacked out of balance, you'd feel awesome, but when it switches on again, baseline firing would be a salient input for a bit and you might notice it? Of course, long term up/down regulation of various receptors occurs too, but I've never heard of this particular effect before though it sounds plausible to me.
    - api 12y ago
      I wondered a while back if (theoretically) taking some kind of non-harmful but pain stimulating compound might not make you feel awesome the rest of the time, and might even be good for you by recalibrating your inflammatory response and such.

raldi 12y ago

He's lucky he didn't do this experiment in today's climate; it would've been the new "shrimp treadmills".

b_emery 12y ago

From near the bottom: "Some further studies failed to reproduce the original experiment's results, but in at least one of these studies[12] both caged and "park" rats showed a decreased preference for morphine, suggesting a genetic difference" Still, it's an intriguing result. The reviewer comments from science and nature would make interesting reading - too bad they are not public.

kbenson 12y ago
But also, from the immediately preceding paragraph: "Several later studies did appear to confirm its findings — for example, Bozarth, Murray and Wise in 1989, also published in Pharmacology, Biochemistry and Behavior — but nothing came of those either." That paints a confusing picture, so without looking at the specifics of the later studies for possible differences, I think it's hard to come to a conclusion.
- bjourne 12y ago
  Wikipedia isn't so good when it comes to drug related topics. Or rather, it is atrocious since the linked study (http://wings.buffalo.edu/aru/HOUSING.html http://wings.buffalo.edu/aru/HOUSING.html) arrives at the completely opposite result Wikipedia claims. It's an interesting read because it also discusses why setting up a study to fairly measure voluntary drug intake among groups of mice is very hard.
  - spb 12y ago
    > it is atrocious since the linked study arrives at the completely opposite result Wikipedia claims. Wikipedia allows public editing. Did you amend the incorrect claim?
  - kbenson 12y ago
    After reading portions of that study, I find it hard to make meaningful comparisons across them. The cited source's two conditions seem to be fairly close in many respects IMHO: "The first group was housed in individual stainless steel cages (18 x 25 x 18 cm) that prevented tactile and visual contact among the rats." "The second condition consisted of rats housed in groups of 10 in a large stainless steel cage (45 x 101 x 39 cm) that permitted social contact; these rats displayed normal play behavior, dominance struggles, and social grooming." Okay, one rat in 450 cm^2 vs 10 rats in 4545 cm^2, both in steel cages. Compared to Rat Park, which was 8.8m^2 (close to twice the size), and was specifically not a steel cage[1]. Then again, I doubt this study was done specifically to confirm or refute the earlier experiment, but to test further hypotheses in the same area. 1: http://www.brucekalexander.com/articles-speeches/rat-park/148-addiction-the-view-from-rat-park http://www.brucekalexander.com/articles-speeches/rat-park/14...

bjourne 12y ago

I'm just gonna be lazy and link to what I wrote the last time the Rat Park page came up on HN: https://news.ycombinator.com/item?id=7743089 https://news.ycombinator.com/item?id=7743089 It comes up a lot, maybe because the result is kind of positive and aligns well with HN's crowds drug liberal views? The RP experiment wrt morphine addiction in mice has not been replicated. Also, afaik, Bruce Alexander had a hypothesis about drug addiction, designed an experiment to prove his hypothesis. Performed the experiment, measured the results and found that they confirmed his hypothesis. It's not a good way to do research. The results of the Stanford Prison Experiment and the Milgram experiments should be discredited for the same reason. Because their results were tainted by their designer. Extraordinary claims requires extraordinary proofs. That mice wouldn't become addicted to morphine is most certainly an extraordinary claim.

shutupalready 12y ago
> had a hypothesis about drug addiction, designed an experiment to prove his hypothesis. Performed the experiment, measured the results That's the very definition of the Scientific Method, so I don't understand what problem you're pointing out: "The overall process of the scientific method involves making conjectures ( hypotheses), deriving predictions from them as logical consequences, and then carrying out experiments based on those predictions." -- from http://en.wikipedia.org/wiki/Scientific_method http://en.wikipedia.org/wiki/Scientific_method (That the experiment has not been replicated as you claim could be a bad sign, but that's a separate matter.)
- nemo1618 12y ago
  The issue is that there's a conflict of interest when the same person who proposed the hypothesis is the same person attempting to prove that hypothesis. This sort of bias is why meta-analysis exists.
- spb 12y ago
  The problem is designing an experiment to confirm the hypothesis rather than to test it.

cthalupa 12y ago

Diacetylmorphine is still used in several European countries as a front line analgesic. Other forms of morphine are widely used for pain relief on a prescribed basis all over. If it is as simple as using morphine addicts you to morphine, why are no much wider swathes of the population addicted to it? I don't know that it's purely environment, but there's plenty of evidence out there that seems to suggest it's more than simply chemical dependency.

vilhelm_s 12y ago
Really? Which countries are those? My impression was that basically the only country that uses heroin for pain relief is the UK, and even there it is basically only used in cases where addition is not an issue, e.g. terminal cancer patients.
- cthalupa 12y ago
  I might have been mistaken on several countries - I can only find sources for it's use in the UK But it is used by first responders as well: http://www.sjtrem.com/content/22/S1/P15 http://www.sjtrem.com/content/22/S1/P15 A decent amount of air ambulances polled use diamorphine. I'm pretty sure (but unfortunately having difficulty sourcing) regular ambulances have it available as well. It's widely used as palliative care in the UK as well, as you pointed out - but it might be worth noting that's not it's sole use, and palliative care doesn't always mean they're going to be dying soon enough that addiction wouldn't be a harmful issue to deal with.

O____________O 12y ago

This was brought up by Johann Hari on the Bill Maher show last week: https://www.youtube.com/watch?v=PxmvFRtYuYQ https://www.youtube.com/watch?v=PxmvFRtYuYQ (I heard that discussion discussed on the Adam Carolla Show from the 10th. I'm guessing it's a hot topic at the moment due to Hari promoting, I think, a book)

geographomics 12y ago

Puts me in mind of a study a few years back where they had socially housed monkeys self-administer cocaine [1]. Like all primates, each group of monkeys ended up with a dominance hierarchy. The most dominant had a relatively nice life compared with the subordinates: more grooming from others, more play, more attention in general. It turned out that the subordinate monkeys were much more susceptible to the temptations of cocaine. In contrast, the dominant ones were able to resist its allure a lot more effectively. The researchers also looked at the neurobiology of the monkeys. Before being socially housed, they were kept in individual cages for a couple of years. They looked at the main pleasure centre of the brain and measured the level of dopamine receptors (of the D2 type) present there. These receptors are directly stimulated by naturally occurring rewards like social activity, food, sex, and so on - but also stimulant drugs like cocaine. All the monkeys had pretty much the same D2 receptor level when they were cooped up in single cages, with little variation. But when they were socially housed, the D2 levels of the dominant monkeys rose significantly higher; this too was associated with their lessened vulnerability to cocaine. So it seemed that social environment can have quite the effect on the neurobiology of one's reward pathway, and potential for drug abuse (as the Rat Park experiment suggested). On reward pathways - in human stimulant addicts you also see lower D2 receptor levels than in non-addicts [2], although this is lacking a comparative reading from before they were addicted, so we don't know if that's near the state they were in when they started abusing the drug. Having said that, in non-addicts there is a natural variation in D2 receptor levels, and those with less D2 enjoy stimulants a lot more [3], just like the subordinate, lower D2 receptor monkeys. Unlike Rat Park, however, all the above is based on stimulants, which directly affect the aforementioned receptors. Whereas morphine takes a more indirect route, with different receptor types, so it's not quite comparable. Still, interesting to think about how much we may be slaves to our neurobiology, and our social surroundings. [1] doi:10.1038/nn798 [2] doi:10.1177/026988119901300406 [3] doi:10.1176/ajp.156.9.1440

MrJagil 12y ago

I would suggest this submission from a few days ago, to anyone interested in the subject: https://news.ycombinator.com/item?id=9029301 https://news.ycombinator.com/item?id=9029301