Addicted Mice Don’t Lack Willpower – They’re Bored


Stephen Luntz

Stephen has a science degree with a major in physics, an arts degree with majors in English Literature and History and Philosophy of Science and a Graduate Diploma in Science Communication.

Freelance Writer

1251 Addicted Mice Don’t Lack Willpower – They’re Bored
Sudokus might not be the answer, but problem solving helps mice to resist addiction. Emily Strange.

Mice given even brief opportunities to solve puzzles are less likely to become addicted to cocaine, a study has found. The research adds to an increasing body of work suggesting that addiction is in large part a reaction to living in an intellectually and emotionally unsatisfying environment, and indicates that intellectual stimulation could be more lasting than has been realized.

Widely reported experiments on rats have shown them quickly becoming addicted to drugs like heroin and cocaine. This fed into panics that people who took these drugs would inevitably become addicted.


Despite this, many people exposed to the drugs use them recreationally or for pain relief and have no withdrawal symptoms if they decide to quit. In the 1970s, Professor Bruce Alexander pointed out that rats are social animals, and this research was done on individuals locked in boring cages without any access to their own kind.

Alexander found that rats housed in a “rat park”, with plenty of fellows, almost never got addicted. The once-neglected work has recently become famous through a book and popular Ted talk by Johann Hari arguing that addiction is a product of isolation.

Dr Linda Wilbrecht of the University of California, Berkeley, looked at stimulation rather than companionship. She found that the company of others is not necessary to keep Mickey off the nose candy, just something to keep his brain stimulated. For nine days Wilbrecht gave male mice a daily chance to explore with a food reward for those who solved problems, while others were kept in boring isolation. A third group was matched with the explorers, with mice getting food whenever their exploring partner solved a problem. A month later, all three sets of mice were exposed to cocaine.

In Neuropharmacology, Wilbrecht reports, the stimulated mice were much less interested in returning to the space where they had got their hit. "We have compelling behavioral evidence that self-directed exploration and learning altered their reward systems so that when cocaine was experienced it made less of an impact on their brain," she said.


Previous research has established that rodents are more likely to get hooked on drugs if they're in a deprived environment, but Wilbrecht wanted to see how short the stimulation could be while still keeping mice on the wagon.

"Our data are exciting because they suggest that positive learning experiences, through education or play in a structured environment, could sculpt and develop brain circuits to build resilience in at-risk individuals, and that even brief cognitive interventions may be somewhat protective and last a relatively long time," Wilbrecht said.

The applicability of rodent research to humans in this area remains disputed. It has been noted, for example, that addiction studies tend to use genetically similar rodents, and may fail to capture the diversity of human genetic susceptibility to drugs. Nevertheless, to the extent that the research is applicable, it looks like the worst possible thing to do to someone with an addiction is lock them in a prison cell or rehab unit without access to mental stimulation.


  • tag
  • addiction,

  • mice,

  • drugs,

  • mental stimulation