Scientists from Vrije Universiteit Amsterdam in the Netherlands have found evidence that being imprisoned for just a few months leads to reduced self-control. Their research was recently published in the journal Frontiers in Psychology.

The new study was based on past research that found impoverished environments are associated with worse cognitive functioning.

“The professor of my department, Erik Scherder (Head of the Section Clinical Neuropsychology, Vrije Universiteit Amsterdam), studied the influence of impoverished vs. enriched environments on elderly people with a neurodegenerative disease such as Alzheimer’s,” study author Jesse Meijers explained.

“When these people are placed into an impoverished environment, their cognitive abilities tend to decline faster than when they stay at home, having more responsibilities, being more active and having more meaningful social interaction.”

“We wondered whether a prison environment, which is inherently impoverished, may have the same effects on prisoners.”

The researchers examined 37 male inmates in a prison in Amsterdam. The inmates completed six psychological tests in the first week of their arrival at the prison and took the same tests again 3 months later.

Meijers and his colleagues found that spending time in prison appeared to have negative psychological consequences for cognitive functioning. They found a “significant deterioration” in both self-control and attention after 3 months of imprisonment.

“Besides being offenders, prisoners are often vulnerable in the sense that they have psychiatric and cognitive disorders, and reduced executive functioning,” Meijers explained to PsyPost. “They are less able than the average individual to be self-supporting, have a legitimate life with housing and income, and maintain relationships.”

“Then, we punish these offenders by removing them from society and placing them in an impoverished environment, expecting that they will have learned their lesson afterwards. However, we now find that their ability to regulate their behavior has been reduced even further, which has major implications for their ability to live the kind of life society expects them to live, outside of crime. If we want to reduce the chances of re-offending, we should think about how we can improve self-control.”

The study has some limitations.

“This study was the first to address the cognitive effects of imprisonment and was done in a relatively small sample,” Meijers said. “Larger studies in different kinds of prisons are needed to confirm the results, especially since prison regimes differ greatly between countries.”

Contrary to their expectations, the researchers found an increase in planning abilities after 3 months of imprisonment. However, this could be caused by a practice effect from taking the same test twice.

“I hope that this study broadens and stimulates the discussion on whether we, as a society, are being effective with imprisonment,” Meijers added. “I also hope that eventually we will aim to improve self-control and executive functions during imprisonment.”

The study, “Reduced Self-Control after 3 Months of Imprisonment; A Pilot Study“, was co-authored by Joke M. Harte, Gerben Meynen, Pim Cuijpers and Erik J. A. Scherder.