Imprisoning convicted criminals serves two primary purposes: (1) to increase the safety of the public by quarantining unlawful offenders, and (2) to rehabilitate those who are incarcerated through punishment. Point 1 is fairly straightforward, but point 2 may be food for thought. Recidivism rates in America have been trending upward, from around 63% in 1983 to around 77% now.
This presents a peculiar contrast to the 40% decrease since 1983 in overall crime. Unfortunately, I haven’t a clue what the correlation is in these statistics (my best guess is that the fringe wrongdoers have “turned things around” while the hard-core offenders remain unmoved). We will, however, examine which criminals are more likely to fly right and which ones are, as far as our justice system is concerned, beyond rehabilitation. 
Justice statistics divide crime into four categories: violent (assault, robbery), property (theft, vandalism), public-order (prostitution, gambling), and drug. Based on “damage to the victim” these would play out, from least to greatest, like this: public-order, drug, property, and violent. Recidivism, however, does not correlate with respect to victimization. Property damage yields the highest rate of re-arrest at 82%. Drug offenders are at 77%, public-order offenders are at 74%, and violent criminals are at 71%. Of the prisoners that were rearrested, 57% of their arrests occurred within the first year of their release. And, in case you’re wondering, the reason homicide doesn’t have its own recidivism category is because murderers are typically not released.
One category of criminal that was not specifically referred to is the type society seems to fear the most: sex offenders. One might suspect that we keep such close tabs on sex offenders because they are, in essence, criminals on the loose. But this is not actually the case. 
Prior to 1996, when Megan’s Law was passed (requiring every state to register sex offenders), sex offender recidivism was around 25%. The reason we treat sex offenders with such disdain is based on the fact that (according to a 2012 report) 26% of sex offender victims are age 12 – 14, and 34% are under the age of 9. Because children are easy targets and rarely report their victimization, the registry system was implemented.
But did this actually deter sex crimes?
When the registry system was first implemented, it was generally ineffective. Washington state showed a minor decrease in sex offender re-arrests of 3% (19% down from 22%). But these procedures improved over time. In 2007, North Carolina made significant changes to their registry system and knocked sex-crime recidivism down to less than 1%. But another factor exists with sex offenders. Registry laws assume that sex crimes are committed by strangers when in fact more than 75% are committed by family members and known acquaintances.
Deterring immorality is generally a function of the people you interact with on a daily basis. If a criminal typically socializes with other criminals, chances are their moral compass will adapt to that environment (i.e., prison politics). If a criminal is effectively shunned, as with North Carolina sex offenders, this seems to have a greater effect, perhaps not with their actual rehabilitation but by limiting their opportunities.
The eternal question of “nature versus nurture” has been extensively studied, especially in regards to criminal and anti-social behavior. An adoption study in Denmark, which utilized a significant sample size of 14,427 adoptees, showed a 7% increase in the likelihood that criminal biology would result in criminal behavior when the host parents were law-abiding. A twin study (sample size of 3,586 pairs), also from Denmark, compared the data of identical twins reared apart to fraternal twins reared apart. Shared criminal behavior was evident in 52% of the identical twins, while only 22% of fraternal twins were concordant.
But it’s not as simple as, say, an isolated genome responsible for morality; it’s a product of our anxiety levels.
Anxiety is generally thought of as a reaction to a stressful environment, but a more prominent foundation for our neurosis is linked to a neurotransmitter called serotonin. Neurotransmitters are microscopic chemicals in our brain that regulate our physiology. In other words, they control almost everything about us. To explain the function of serotonin in non-clinical terms, it calms us down. Genetically lower serotonin levels are associated with some common anxiety related disorders, like OCD and depression. In the context of morality, a calmer person would view society more favorably and consider alternative options to acquiring income than, say, stealing a car.
A very telling but elusive sign of the genetic links to criminal behavior is demonstrated in one of our most primitive natural instincts: revenge. The propensity for revenge and retaliation, demonstrated in both humans and animals, can be viewed as a means of artificial selection, or a method to prevent the immoral from procreating — basically a judicial version of “survival of the fittest.”
The environmental element in criminal behavior is actually demonstrated in the statistics themselves. The criminal category most directly associated with one’s environment (specifically “economic status”) is property crime, which has the highest rate of recidivism.
Unfortunately, there are very few environmental ways to boost our serotonin levels, but perhaps the most crucial is proper maternal nurturing. Studies have linked lower levels of serotonin in monkeys to a “peer-raised” upbringing versus a “mother-raised” upbringing.
The lesson here, if you want to reduce crime, is fairly simple: choose a law-abiding mate, and nurture your kids.
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image illustrations via shutterstock / Dmitrijs Bindemanis / Twin Design / Creations
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