Uncommon Knowledge

The pace of insurgent innovation

A member of the US Army's explosive ordinance disposal (EOD) unit scans the area around a burning M-ATV armored vehicle after it struck an improvised explosive device (IED) near Combat Outpost Nolen in the Arghandab Valley north of Kandahar July 23, 2010. REUTERS/Bob Strong (AFGHANISTAN - Tags: CONFLICT MILITARY) Library Tag 07242010 National/Foreign
REUTERS/Bob Strong
A member of the US Army’s explosive ordinance disposal unit scans the area around a burning M-ATV armored vehicle after it struck an improvised explosive device (IED) near Combat Outpost Nolen north of Kandahar on July 23, 2010.


The United States has spent tens of billions of dollars in Iraq and Afghanistan on technology and equipment to counter improvised explosive devices, the roadside bombs also known as IEDs. But in an analysis of declassified data on “36,681 IED detonations, 43,420 IED neutralizations, and 14,578 weapon cache discoveries” in Afghanistan from 2006 to 2014, researchers found “bombs were just as likely, if not more, to detonate and cause harm to combatants at the end of the conflict as they were at the beginning (and periods in between).” In other words, insurgent innovation in IED deployment kept pace with counter-insurgent innovation in IED defense.

Trebbi, F. et al., “Insurgent Learning,” National Bureau of Economic Research (June 2017).

Kick-starting privilege

An analysis of thousands of projects listed on the crowdfunding website Kickstarter found that black entrepreneurs (as identified by posted photos) were much less likely to be funded, even controlling for gender, number of Facebook friends, fundraising goal and incentives, and the quality of the video pitch. But they were just as likely as other entrepreneurs to deliver on funded projects. In experiments, participants judged projects by hypothetical black entrepreneurs to be of lower quality than identical projects by hypothetical white entrepreneurs — even controlling for participants’ own explicit assessments of the entrepreneur’s ability to deliver — suggesting that the bias was largely unconscious. The bias was eliminated by showing that others were supporting the project, by indicating that other black entrepreneurs had been successful, or by simply removing signs of race.

Younkin, P. & Kuppuswamy, V., “The Colorblind Crowd? Founder Race and Performance in Crowdfunding,” Management Science (forthcoming).


Scoring social justice

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To judge from surveys of sub-Saharan African and Muslim immigrants in Belgium, a significant amount of anti-Semitic sentiment is the result of feeling that recognition of Jews’ suffering in the Holocaust has overshadowed the victimization of one’s own group. This pattern was replicated in an experiment. After being led to believe that business students had hacked into a school computer and caused law and psychology students to fail an exam, psychology students felt significantly less positive about the law students if the administration had recognized only the law students as victims

De Guissmé, L. & Licata, L., “Competition over Collective Victimhood Recognition: When Perceived Lack of Recognition for Past Victimization Is Associated with Negative Attitudes towards Another Victimized Group,” European Journal of Social Psychology (March 2017).

The depleted West

Imagine doing something that requires a lot of concentration. Would you expect to be mentally depleted afterwards? According to a new study, Westerners would, but people in India wouldn’t. Moreover, this is a self-fulfilling prophecy. Not only do Indians tend to believe that concentration is energizing (i.e., makes subsequent concentration easier), but it actually is energizing for them. American and Swiss people tended to believe in depletion and actually did become depleted. An antidote to Western depletion was to make people read a “research article” arguing that concentration is energizing.

Savani, K. & Job, V., “Reverse Ego-Depletion: Acts of Self-Control Can Improve Subsequent Performance in Indian Cultural Contexts,” Journal of Personality and Social Psychology (forthcoming).

Not pregnant with possibilities


Economists found that states that required insurers to cover infertility treatment, particularly in-vitro fertilization, saw relatively more growth in the share of women with professional degrees and working in professional occupations. In addition to affecting the decision to pursue a profession, the mandates also appear to have spurred migration of professional women into the state.

Kroeger, S. & La Mattina, G., “Assisted Reproductive Technology and Women’s Choice to Pursue Professional Careers,” Journal of Population Economics (July 2017).

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