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    Uncommon Knowledge

    Why the act of collecting DNA from convicts deters crime

    Handcuffs hang on the wall inside Lafayette Parish jail in Lafayette, La., April 19, 2016. Louisiana and some other states with criminal justice systems that treat 17-year-olds as adults appear to be on the verge of raising the cutoff to the more standard age of 18. (William Widmer/The New York Times)
    William Widmer/The New York Times
    Handcuffs hung on the wall inside a jail.

    Covering up the testimony

    Some Western judges have required Muslim women to remove their veils before testifying, ostensibly because a veil makes it harder to judge credibility. However, new research suggests otherwise. Women were recruited to be witnesses and “were shown a video of a woman who was watching a stranger’s bag. As determined by random assignment, half of the women also observed her stealing items from the bag. Then, all of the witnesses were informed that the woman had been accused of theft and they were being called to testify on her behalf (i.e., they were to state that they did not see her steal anything). . . . Once they were prepared, witnesses were randomly assigned to don a black niqab, a black hijab, or remain unveiled.” Other participants were recruited to watch the videos of the witness interviews and assess veracity. Women who wore niqabs or hijabs were judged more accurately.

    Leach, A.-M. et al., “Less Is More? Detecting Lies in Veiled Witnesses,” Law and Human Behavior (forthcoming).

    Making America pray again

    If you’re on the religious right and you lament the secular left, there’ll be a nice bonus from a Trump presidency: Democrats finding religion. A new study finds that, compared to Democrats, Republicans were more likely to attend religious services and pray in the weeks after the 2012 election compared to the weeks before the election. This was especially true for Republicans who thought Mitt Romney would win. Survey data going back several decades also reveal that “despite Republicans being more religious than Democrats both when [Bill] Clinton and George W. Bush were president, the religious gap between Republicans and Democrats that had expanded during Clinton’s presidency actually became smaller when George W. Bush was president.”

    Margolis, M., “Cognitive Dissonance, Elections, and Religion: How Partisanship and the Political Landscape Shape Religious Behaviors,” Public Opinion Quarterly (forthcoming).

    Me, myself, and I

    Perhaps it’s art imitating culture, or culture imitating art. An analysis of the lyrics of Billboard Hot 100 songs from 1990, 2000, and 2010 reveals that hit songs have become more narcissistic. “Specifically, songs in 2010 were significantly more likely to have the singer refer to self by name (26 percent in 2010 compared with only 9 percent in 1990) and general self-promotion (24 percent in 2010 compared with only 3 percent in 1990). There was also a significant increase in the number of songs containing artists bragging about their wealth and possessions (22 percent in 2010 compared with 6 percent in 1990). Other forms of bragging (about their partner’s appearance and their own sexual prowess or exploits) also significantly increased in frequency over the time period.” Rap music is only part of the story; self-promotion “has spread to other genres such as R&B, dance/electronic, and pop.”

    McAuslan, P. & Waung, M., “Billboard Hot 100 Songs: Self-Promoting over the Past 20 Years,” Psychology of Popular Media Culture (forthcoming).

    The other CSI effect


    Some have suggested that crime shows lead the public — and thus jurors — to expect amazing evidence at trial. But there’s also good news from the forensic-science department. The act of collecting DNA from convicts deters crime. Comparing recidivism rates for convicts who were released before a collection requirement went into effect to recidivism rates for convicts released after the requirement, an economist found that “the requirement to submit a DNA sample reduces the likelihood of a new conviction within five years by 4.5 percentage points (17 percent) for serious violent offenders.” And given that the incremental cost of collecting DNA from each convict is small, the incremental cost of preventing a serious crime through DNA profiling is estimated to be a tiny fraction of the incremental cost of preventing a serious crime from longer prison sentences or more police officers.

    Doleac, J., “The Effects of DNA Databases on Crime,” American Economic Journal: Applied Economics (forthcoming).

    Masters of disasters

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    Elon Musk, the pioneering CEO of electric-car maker Tesla and rocket company SpaceX, is lucky that he didn’t grow up in the severe climate-change scenarios that he now worries about. A study found that companies run by CEOs who grew up in counties that experienced severe natural disasters are more averse to risk — taking on less debt, making less-aggressive acquisitions, and exhibiting less stock volatility — even controlling for a county’s typical incidence of disaster. On the other hand, companies run by CEOs who grew up in counties that experienced moderate natural disasters exhibit the opposite pattern — extra risk.

    Bernile, G. et al., “What Doesn’t Kill You Will Only Make You More Risk-Loving: Early-Life Disasters and CEO Behavior,” Journal of Finance (forthcoming).

    Kevin Lewis is an Ideas columnist. He can be reached at