If you were asked whether you’d prefer to be given $140 today or $1400 in five years' time, the smart answer is obvious. But immediate cash can be really tempting: perhaps you have expensive car repairs looming or you want to buy a gift for someone—that $140 would do the trick. It can be easy to justify cheating your future self out of $1260 in the face of instant gratification.

The tendency to ignore or discount the value of a future benefit is called "time discounting." Plenty of research suggests that time discounting can be linked to criminal behavior, which is the ultimate example of choosing an immediate reward despite an abstract risk of losses. Although the link is intuitive, it still needs confirmation through empirical research, because so many things that seem intuitive turn out to be wrong.

Investigating this question is a tough gig, though. You could test people’s time discounting behaviors and look at their criminal records, but even if you found a link, you wouldn't know whether the time behaviors led to the crime, or vice versa. Ideally, you need to find a way to test children’s time discount rates, and then wait to see if they get involved in crime as adults (and whether this tendency lasts past the adolescent crime peak).

Creating this data would require waiting decades, and most funders aren't that patient. Instead, researchers in Sweden turned to data collected in the past. They started with a 1966 survey conducted on every 13-year-old who went to school on a particular day in Stockholm. Because 13,606 children spanning all socioeconomic classes took part, the researchers were confident that the sample would be representative of the population at large.

One piece of data collected in the survey was time discount rates. Kids were asked the exact same question we started the article with (except using Kroner instead of dollars). Because the respondents were linked up with their administrative records, including data on crime, it was also possible to see what happened to these children over the next 18 years, until the age of 31.

The researchers emphasize that they’re not trying to make strong claims about causation with this work. It’s possible that time discounting causes crime, but there are so many additional factors that it’s difficult to say for sure. What’s important, they say, is prediction: if we know something about a child’s time discounting tendencies, can we predict their risk of criminal involvement and perhaps introduce ways to reduce that risk.

Despite their caution about making causal claims, the researchers controlled for other factors that could be involved. One of these is family background, including how educated the children’s parents are and how much they earned, as poverty has a strong influence on crime.

The authors' analysis found that time discounting rates do significantly predict criminal activity. Children who said they would prefer to delay their reward were 33 percent less likely than average to have at least one criminal conviction. However, time preferences play less of a role than other factors captured in the survey, like cognitive ability.

The predictive power of time discounting also did not work across all scenarios: it did a better job of predicting property crimes than violent crime. The researchers think this points to time preference being very different from self control: where a lack of control might lead to crimes of passion, they suspect property crimes are more a case of planning to get a reward now despite future penalties.

This suggests that harsher penalties for crime don’t make much of a difference to crime rates. If criminals have “short time horizons,” the Swedish researchers write, “the delayed costs do not motivate them to refrain from criminal activities, and punishment may not act as a key deterrent.” Instead, they suggest that policies making it more likely that criminals are caught immediately, like surveillance cameras, could be more effective. They also highlight the importance of education in helping children to shape better time preferences, although it’s not clear yet whether this works.

This study is still exploratory, so hopefully there’ll be more work done with this very useful data set. And while it certainly doesn’t mean that every child who chooses instant gratification is a budding little criminal, it does provide a potentially useful way to find children who are at higher risk.

PNAS, 2016. DOI: 10.1073/pnas.1522445113 (About DOIs).