What does prison accomplish?

Why do we send people to prison?

Well, they did bad things. They should be punished.

An Age of Enlightenment idea, prison was considered a “humane” approach to punishment–far better than cutting off a hand, sticking a hot a poker in the eye, burning at the stake or stoning to death.

But in addition to punishment, incarceration is believed to serve several other purposes. One is incapacitation—preventing crime by removing and restricting the criminal. Another is deterrence—preventing future crime by making the period of incarceration not an experience someone would like to repeat. A third is rehabilitation, the belief that time in prison can be used to help those who’ve committed crimes become the kind of people who will no longer commit crimes.

Arguments can and have been made about the concept of punishment: How much is enough? Should being imprisoned be the punishment or should the daily life of a prisoner inflict punishment? Is being held in isolation cruel and unusual punishment? Death penalty or not?

Arguments can and have been made about rehabilitation: Can people really change? Is providing programming and education in prison being “soft” on crime?

But few have argued against the (presumably self-evident) functions of incapacitation and deterrence. Until now.

A new study (12 years of data from 110,000 convicted felons) conducted by a team of researchers from Berkeley, University of Michigan, SUNY/ Albany, and Colorado, and published in Nature, the pre-eminent science journal, concludes…prepare to gasp:

Prison did not reduce post-release violent crimes.

The study found that sentencing someone to prison had no effect on their chances of being convicted of a violent crime within five years of being released from prison. (The study compared post-release arrests of those who served prison sentences with those put on probation.)

In terms of incapacitation, the study found a preventative short term effect (the time when prisoners were still in prison), but this effect was smaller than assumed. Preventing one person who was previously convicted of a violent crime from committing a new violent crime within five years of their sentence required (statistically speaking) imprisoning 16 such individuals.

The authors bring up related points worth considering:

Imprisonment, because of the culture behind bars, could actually increase a person’s propensity towards violence.

Imprisonment can (has been shown to) exacerbate pre-existing mental health problems or cause new ones that may increase the risk of engaging in violence or being victimized by violence.

Prison life and prison culture can lead to the development or reinforcement of behaviors and attitudes that will make a successful, crime-free life on the outside more difficult. For example: distrust of authority; aggressive coping strategies; lack of self-efficacy and initiative; hypervigilance.

Incarceration, especially long-term incarceration, can erode the familial and social networks that support and encourage a crime-free future.

The authors conclude, from the evidence, that imprisonment does not appear to accomplish what we think it should, what we assumed it did.

What are the choices here? Abolish prisons? Not likely. Ignore the evidence and keep on doing what we are doing? Not smart. Re-think and re-design our current corrections system? Yes.