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    The "Rat Park" Study: 40 years later

    16th July 2019

16th July 2019

The "Rat Park" Study: 40 years later

Psychologist Dr. Bruce Alexander published his groundbreaking “Rat Park” study just a hair over 40 years ago. This groundbreaking study changed the way the world thought about the nature of addiction completely. That’s why, a full 40 years after it was originally published, it’s still being discussed, celebrated, and criticized today - maybe more so now than ever before. What was Dr. Alexander’s “Rat Park” study, and why is it still generating debate as it reaches middle age?  

What was "Rat Park"?

Since the 1930s, scientists had been using a device called the “Skinner Box”, essentially a small box with a light, a tube for food, and a tube with which rats could self-administer water mixed with various substances. Studies that used the Skinner Box reinforced what scientists already believed about addiction: that the inherent properties in intoxicating substances caused dependence. The Rat Park study upended this easy tautology. Dr. Alexander put his rats in a much larger space. They were given access to toys, exercise equipment, and other rats to fulfill their social and sexual needs. Alexander found that the rats who lived in a happy, communal environment were far less likely to become addicted to substances than were isolated rats.

A Digression

Why are all of these studies conducted on rats? One reason is that rats have a similar genome to humans. Human genes associated with disease generally have an equivalent in rat genomes. Another is that, like humans, rats are a social species who generally live in close proximity to others of their species and communicate with each other regularly. Other reasons include wide availability, size, fast reproductive rates, low cost, and ease of handling.

The Study

Alexander took 4 groups of rats. The first was isolated in Skinner Boxes. The second lived in rat park. The third was placed in isolation for the first half of the study and moved to Rat Park for the second half. The fourth group began in Rat Park and were moved to isolated cages halfway through. All of the rats were given the option of drinking tap water or water infused with a sweetened morphine solution.

The results showed that rats who were in a comfortable, social environment were far less likely to use, or become dependent on, morphine than isolated rats. The caged males drank 19x more morphine than the males in Rat Park. The rats of both sexes housed in Rat Park showed a strong preference for plain water. The most interesting group was the group moved from cages to the Rat Park. They “rejected the morphine solution when it was stronger, but as it became sweeter and more dilute, they began to drink almost as much as the rats that had lived in cages.” This led Alexander to conclude that the rats preferred the sweetened water, but didn’t want it to disrupt their normal social behavior.

Alexander felt that the results of his study disproved theories of drug-induced addiction. He felt that normal humans and animals could ignore, and even use, substances such as opiates without becoming addicted. He believed that addiction was caused by social isolation and environmental stress. Alexander’s pithy conclusion was “Addiction isn’t you- It’s the cage you live in.”

The Criticism

Asserting that drugs weren’t the central problem in addiction was an extremely controversial statement in 1980, as the War on Drugs was at its height. The US government was spending trillions of dollars enforcing draconian drug laws and broadcasting ads like this one. The first two science publications that Alexander took his results to, “Science” and “Nature,” both rejected the study, but Alexander’s results were accepted and published by the journal “Pharmacology Biochemistry and Behavior.”

Critics of the study have pointed to flaws in methodology and implementation. A malfunctioning electronic device lost 8 days of data on the amounts of liquid the rats consumed. The isolated rats were denied proximity to rats of the opposite sex, and the rats in Rat Park had pups during the study (the effects of pregnancy and childbirth could have influenced the study, and Alexander makes no mention of whether the pups were left in the park or not). Dr. Sam Snodgrass, a Director of the substance abuse support organization “Broken No More”, argues that  “You can’t do this. You can’t have one group of subjects mating and with pups and compare it to a group that doesn’t engage in these behaviors and say that the difference between the two groups is caused by environmental differences.”

A new understanding

The study, which was largely dismissed when published, surged into the limelight in the 1990s, as what Alexander referred to as “The Myth of the Demon Drug” fell out of favor, and increasing numbers of doctors, journalists, and scientists began to explore the nature of addiction with open minds. A 1996 study attempted to replicate the experiment, with mixed results. Meanwhile, Dr. Gabor Mate brought public attention to the Rat Park study and statistics from the Vietnam War, which showed that soldiers in combat zones used 20x more heroin than they did pre and post-deployment. Johann Hari’s influential Ted Talk on addiction brought even more attention to the study. It even inspired a re-telling in comic book form! Meanwhile, pieces like this one in “Psychology Today” argue that the study promotes an unrealistic and irresponsibly simplistic view of addiction.

The study remains a hot-button topic for anyone concerned with addiction. It is now controversial because it appears to challenge the “disease model” of addiction, which focuses on genetic and neurological factors, rather than emphasizing the importance of social and psychological factors. Regardless of whether Alexander’s experiment was flawed, it has inspired more thought, research, debate, and insight into the nature of addiction than almost any other experiment. Perhaps most importantly, it has also shown us the importance of emphasizing social re-integration and psychological health in the treatment of addiction.


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