Uncommon Knowledge: Researching the impact of milder temperatures

Shutterstock/Marian Weyo

By Kevin Lewis  


A team of researchers in the United States and China found that, across both countries, people who grew up in locations where the average temperature was closer to 22 degrees Celsius (71.6 degrees Fahrenheit) — in other words, neither Boston nor Phoenix — tend to have more appealing and flexible personalities, even controlling for other local factors like disease, agriculture, demographics, and the economy. The theory is that mild temperatures “encourage individuals to explore the outside environment, where both social interactions and new experiences abound.”

Wei, W. et al., “Regional Ambient Temperature Is Associated with Human Personality,” Nature Human Behavior (December 2017).

Family values

Because births in certain countries peak in September, some scholars have theorized about a seasonal cycle of human reproduction, perhaps aligned with the December solstice and the environmental changes that accompany it. In contrast, a new paper finds that holidays are more important. Internet searches related to “sex” peaked around Christmas — and births likewise increased nine months later — in Christian countries in the Northern Hemisphere, where winter begins in December, but also in the Southern Hemisphere, where the December solstice ushers in the summer. There was no such surge in sex-related searches for other holidays, or in the same time frame for Orthodox Christian countries that celebrate Christmas later. In Muslim countries, a similar uptick in searches occurs around Eid al-Fitr and Eid al-Adha — which fall at varying times of the solar year, because Muslim holidays follow a lunar calendar.

Wood, I. et al., “Human Sexual Cycles Are Driven by Culture and Match Collective Moods,” Scientific Reports (December 2017).

Survival of the most diverse


Economists found that counties that started out with more immigrant genetic diversity — whether measured in 1870 or as far back as 1790 — experienced more economic development in subsequent decades, even up to today.

Ager, P. & Brueckner, M., “Immigrants’ Genes: Genetic Diversity and Economic Development in the United States,” Economic Inquiry (forthcoming).

Provisional voting

An analysis of survey data found that support for a voter ID requirement was stronger among Republicans, even controlling for political ideology, support for equal rights and immigration, interest in politics, knowledge of the state’s ID law, and a respondent’s age, education, and gender. More surprising, however, an experiment with a nationwide sample of Americans found that informing them of the (minuscule) frequency of documented cases of voter fraud actually increased Republican support for voter ID — whereas telling Republicans it would help or hurt Republican turnout didn’t matter. Democrats, on the other hand, were significantly swayed by turnout information, such that they became almost as supportive of voter ID as Republicans if told it would help Democratic turnout.

Kane, J., “Why Can’t We Agree on ID? Partisanship, Perceptions of Fraud, and Public Support for Voter Identification Laws,” Public Opinion Quarterly (Winter 2017).

Best company to work for?

Analysis of jury verdicts in employment discrimination cases against large companies revealed that companies with better reputations, beyond their financial metrics, were more likely to be found not liable, even controlling for type of discrimination, jurisdiction, and the industry and size of the company. However, juries assign greater punitive damages to companies with better reputations if found liable.

McDonnell, M.-H. & King, B., “Order in the Court: How Firm Status and Reputation Shape the Outcomes of Employment Discrimination Suits,” American Sociological Review (forthcoming).

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