Addiction: The View from Rat Park

Bruce K. Alexander,Professor Emeritus, Simon Fraser University



If you were a cute little white rat…

Figure 1 - White Rats



…you certainly wouldn’t want to live in a psychology laboratory.



When I was an experimental psychologist, between about 1960 and 1980, white laboratory rats had to live in solitary confinement cellblocks like this…

Figure 2 - Standard Rat Housing



Although the rats lived in close proximity, they could neither see nor touch each other, because the sides of their cages were made of sheet metal. The only visual stimulation they got was seeing the people who brought food and water and cleaned the metal pans under their cages every few days. Unlike human prisoners, the rats did not even get an exercise period outside their cramped cages.

And that was in the best of times. In the worst of times they were starved for 24 hours or more and put into Skinner Boxes that looked like this…

Figure 3. Skinner Box

Inside Skinner Boxes, the rats could get tiny pellets of food one at a time, provided they pushed a little lever on the side of the box over and over and over. The metal floor made it possible for the experiment to administer electric shocks when the experiment was about punishment rather than reward, which it often was.

Do you think that this would qualify as psychological abuse of rats? Of course it would, if there were such a crime. But we young psychologists were trained not to think about what the rats might be experiencing. We usually did not even look at the rats, but only at the data they produced in the Skinner Boxes by pressing their little levers. The data looked like this...

Figure 4 – Skinner Box Data

Do you see any sign of rat angst or depression in these data? If not, the rats must be ok, right?

In the 1960s, some experimental psychologists began to think that the Skinner Box was a good place to study drug addiction. They perfected techniques that allowed the rats to inject small doses of a drug into themselves by pressing the lever. This required tethering the rat to the ceiling of the box with tubing and surgically implanting a needle, or catheter, into their jugular veins. The drug passed through the tube and the needle into the rats’ bloodstreams almost instantaneously when they pushed the lever. It reached their brains moments later.

Under appropriate conditions, rats would press the lever often enough to consume large amounts of heroin, morphine, amphetamine, cocaine, and other drugs in this situation.



The mass media of the day were quite excited about these experiments. The results seemed to prove that these drugs were irresistibly addicting, even to rodents, and by extension, to human beings. The conclusion that illegal drugs are irresistibly addicting fit well with the fearsome images that were being propagated about them. The rat research provided additional support for the War on Drugs of that day. Irresistibly addicting drugs certainly cannot be allowed to circulate in human society, especially if, as we were told, this is your brain on drugs…

Figure 5 – Frequently broadcast Fried-egg Image of Addictive Drugs (1987)

At first, the conclusion that was reached from this rat research made sense to me. But then I began to realize that it was a stretch. Actually, it was more than a stretch; it was a bone-cracking, joint-popping contortion of normal reason, for several reasons. First, the ancestors of laboratory rats in nature are highly social, sexual, and industrious creatures. Putting such a creature in solitary confinement would be the equivalent of doing the same thing to a human being. Solitary confinement drives people crazy; if prisoners in solitary have the chance to take mind-numbing drugs, they do. Might isolated rats not need to numb their minds in solitary confinement for the same reason that people do? Second, taking drugs in a Skinner box where almost no effort is required and there is nothing else to do is nothing like human addiction which always involves making choices between many possible alternatives. Third, rats are rats. How can we possibly reach conclusions about complex, perhaps spiritual experiences like human addiction and recovery by studying rats? Aren’t we more complex and soulful than rats, even if we have similar social needs?

A small group of colleagues at Simon Fraser University, including Robert Coambs, Patricia Hadaway, Barry Beyerstein, and myself undertook to test the conclusion about irresistibly addicting drugs that had been reached from the earlier rat studies. We compared the drug intake of rats housed in a reasonably normal environment 24 hours a day with rats kept in isolation in the solitary confinement cages that were standard in those days. This required building a great big plywood box on the floor of our laboratory, filling it with things that rats like, such as platforms for climbing, tin cans for hiding in, wood chips for strewing around, and running wheels for exercise. Naturally we included lots of rats of both sexes, and naturally the place soon was teeming with babies. The rats loved it and we loved it too, so we called it “Rat Park”.

Figure 6a – “Aerial View” of Rat Park, North Wing



Figure 6b – Naptime and Recess



Figure 6c – There are Always Some who Prefer the Rat Race



Figure 6d – Just Hanging Out

We ran several experiments comparing the drug consumption of rats in Rat Park with rats in solitary confinement in regular laboratory cages. In virtually every experiment, the rats in solitary confinement consumed more drug solution, by every measure we could devise. And not just a little more. A lot more.

Here are the results of one of our first experiments.

Figure 6e – A Mother with Pups Rat Mother with Pups



You will see at a glance that the rats in Rat Park, called the “Social Females” and “Social Males” in this graph, are consuming hardly any morphine solution, but the “Caged Females” and “Caged Males” are consuming a lot. In this experiment the females consumed more than the males, but that gender difference did not hold up in later experiments.



It soon became absolutely clear to us that the earlier Skinner box experiments did not prove that morphine was irresistible to rats. Rather, most of the consumption of rats isolated in a Skinner box was likely to be a response to isolation itsself. So, we published the results of our experiments in psychopharmacology journals.

Fig 7 - Some Experimental Results



The Rat Park research attracted lots of attention in the local media in our city, and among our students at our university, but in the larger world of addiction theory it sank like a stone, even after other researchers replicated our findings. We had hoped that our research might initiate a serious reconsideration of the conventional wisdom on the causes of addition. When it didn’t, we were surprised and disappointed. However, we were all at an early stage in our professional careers and looking for other issues to tackle. After our satisfying, but unheralded, success with Rat Park, our individual interests took us off in separate directions.

One of the worst aspects of closing of Rat Park was that it left us with unresolved questions. A new graduate student in our lab had tried to replicate one of our original experiments but did not get statistically significant results. Non-replication is not a fatal problem in laboratory research, but it requires follow up studies to determine why it happens. Many factors can determine the outcomes of experiments and not all ofthem can be controlled. Did the non-replication occur because the researcher had to use a new substrain of rats, or because the modified, presumably improved, apparatus that measured drug and water consumption in Rat Park didnot work as well as the original machinery, or simply because the Rat Park effect was not as robust as we originally thought? We never were able to work out the mystery, because Rat Park was closed down for good. However, we remain confident in our original experiments, partly because we had repeated them several times in different ways, partly because they were replicated with different apparatuses by researchers at other universities, and partly because more recent research with different methods has shown other fatal deficiencies in the original Skinner box research which once appeared to show that all rats and people who use addictive drugs become addicted.

But a vague question lingered in my mind. Our rats consumed much more morphine when they were isolated. This fact definitely undermined the supposed proof that certain drugs irresistibly cause addiction. But what does cause addiction? Why is there currently a flood of addiction to drugs and many other habits and pursuits? People do not have to be put into cages to become addicted – but is there a sense in which people who become addicted actually feel “caged”?



It turns out that the answer to this last question is “yes”. Or rather, “YES!” The insight into human addiction that grows from the Rat Park research is not terribly complicated, but it took me about 15 years to grasp it clearly and another 10 years to assemble the evidence from human history and anthropology to show that it is true and another 5 years to write a book about it. (The Globalisation of Addiction: A study in poverty of the spirit, Oxford University Press, 2008). That’s how I got to be an old guy.

My graduate students and I first tried to replicate part of the Rat Park research with human beings, by getting people to role-play prisoners and guards in a prison. The idea was that the prisoners in a simulated prison would be in the same state of mind as the rats in Rat Park. We couldn’t offer them drugs of course, but we could at least ask them about how they felt and get an idea of the mindset that is conducive to consumption of drugs. Unfortunately, the experiment told us nothing…Back to the drawing board.

How could we do an experiment with people that was something like Rat Park, without treating our human subjects unethically or illegally? I gradually realized that history provides natural experiments of the sort I needed. The results are sitting around in dusty books just waiting to be analyzed. One of these many natural experiments is the effect of colonization on native people.

Here are the basic facts as they are recorded in the history of Western Canada, where I live, although very similar historical data can be found in many countries:

The English colonial empire overran hundreds of native tribal groups in Western Canada in the 18th and 19th century. The native people were moved off expansive tribal lands onto very small reserves, completely destroying the economic basis of their cultures. Their children were taken from their parents and sent off to “residential schools” to be taught the white man’s culture so they could be assimilated. They were forbidden to speak their native languages and found themselves strangers in their own communities when they finally came home.

Prior to the colonial conquest, the native people had some serious problems, of course, including frequent tribal warfare, with prisoners being killed or kept as slaves. Mental illness, personal betrayals, and epidemic diseases occasionally occurred in pre-colonial tribes. Basically, native people had all the problems of their English colonizers except one. There was so little addiction that it is very difficult to prove from written and oral histories that it existed at all.

But once the native people were colonized alcoholism became close to universal. There were entire reserves where virtually every teenager and adult was either an alcohol or drug addict or “on the wagon”. There still are a few reserves like this. Addiction was not limited to alcohol, but eventually encompassed the full range of addictions found in the wider society: drugs, television, gambling, Internet, dysfunctional love relationships, etc.

At first, the English settlers explained the universal alcoholism of the natives with the a story of genetic vulnerability. They said “Indians just can’t handle liquor” and tried to solve the problem with strict alcohol prohibition. That didn’t work and most people don’t believe the genetic vulnerability story anymore.

So why did universal addiction strike the colonized natives of Western Canada and the world as well? Certain parallels between the problems of colonized human beings and the rats in Rat Park appear to provide an explanation. In both cases there is little drug consumption in the natural environment and a lot when the people or animals are placed in an environment that produces social and cultural isolation. In the case of rats, social and cultural isolation is produced by confining the rats in individual cages. In the case of native people, the social and cultural isolation is produced by destroying the foundations of their cultural life: taking away almost all of their traditional land, breaking up families, preventing children from learning their own language, prohibiting their most basic religious ceremonies (potlatches and spirit dancing in Western Canada), discrediting traditional medical practices, and so forth. Under such conditions, both rats and people consume too much of whatever drug that is made easily accessible to them. Morphine for the rats, alcohol for the people.

In both cases, the colonizers or the experimenters who provide the drug explain the drug consumption in the isolated environment by saying that the drug is irresistible to the people or the rats. But in both cases, the drug only becomes irresistible when the opportunity for normal social existence is destroyed.

In the case of natives of Western Canada, other historical information makes it perfectly clear that a simple genetic vulnerability to alcohol was not the cause of the devastating plague of alcoholism that occurred. There are several different types of evidence:

1. In cases where alcohol was available to natives, but their cultures were not destroyed, they were able to incorporate alcohol into their native traditions without too much trouble. People drank and some people got plenty drunk on some occasions, but there was no widespread alcoholism.

2. In cases where native cultures were destroyed, but alcohol was not available, native people showed many of the symptoms that are associated with mass alcoholism, without ever tasting a drop. In other words, people stopped doing productive work and taking care of their families and concentrated on aping the manners of the English invaders and idling away their time. Criminality and child neglect became problems, where they had not been before. But alcohol was not the cause because there wasn’t any!

3. We now know that native people whose cultures have been destroyed are vulnerable to all the addictions that white people are. If Indians whose cultures have been destroyed have a genetic weakness for alcohol, they also have a genetic weakness for drugs, television, gambling, bingo, Internet, and dysfunctional love relationships!

If the alcohol itself was not the cause of native alcoholism, what was? The great advantage of doing our research with human beings rather than rodents is that people are often willing to tell us the answer to our questions. Native people have described the anguish of being deprived of their traditional cultures and social networks in eloquent language and have explained how drunkeness relieved their misery temporarily, even as it ultimately led to self-destruction.

Fig 8

When I look at the pictures of our caged rats now, it is easy for me to think that I detect something similar to the anguish or rage that native people describe when their cultures are destroyed. However not everyone agrees. Some people seem to think that rats are pretty inscrutable.



There is no way to resolve an argument what rats are feeling. So I have never gone back to rat experimentation but have instead searched out more and more parallels in the literature of human history and anthropology. This work is still in progress. There is no shortage of parallels from people of all races and many cultures.

When I talk to addicted people, whether they are addicted to alcohol, drugs, gambling, Internet use, sex, or anything else, I encounter human beings who really do not have a viable social or cultural life. They use their addictions as a way of coping with their dislocation: as an escape, a pain killer, or a kind of substitute for a full life. More and more psychologists and psychiatrists are reporting similar observations. Maybe our fragmented, mobile, ever-changing modern society has produced social and cultural isolation in very large numbers of people, even though their cages are invisible!



The view of addiction from Rat Park is that today’s flood of addiction is occurring because our hyperindividualistic, hypercompetitive, frantic, crisis-ridden society makes most people feel social and culturally isolated. Chronic isolation causes people to look for relief. They find temporary relief in addiction to drugs or any of a thousand other habits and pursuits because addiction allows them to escape from their feelings, to deaden their senses, and to experience an addictive lifestyle as a substitute for a full life.



At this point, it is too early to say conclusively if the Rat Park view of addiction is right or not, but it is not too early to be sure that the old theory that addiction is a problem caused by addictive drugs is far too simple. Huge amounts of research money have been spent researching the idea that addictive drugs are the cause of addiction and treatments based on that idea have been tried over the world. In the meantime, the once-small problem of addiction has globalized. Moreover, it has become absolutely clear that drug and alcohol addiction is only a corner of a much larger addiction problem!

It is definitely time for a fresh direction in the theory of addiction, and I have a hunch – as well as a hope – that Rat Park might provide the starting point. The next steps from this starting point are explained in my book The Globalization of Addiction: A study in poverty of the spirit. (Oxford Univ. Press, 2010).