Volume 5 Issue 2, February 2021

Scientific research can have a positive impact on society, particularly in a health crisis. But to fully achieve this, scientists must engage with end-users from the very beginning of the research process, writes Lea Pare Toe.

The harassment of researchers working in the social sciences—not rarely an organized effort targeting members of marginalized groups—is most alarming. Its implications reach from severe personal consequences to the risk of scientific self-censorship. We invite readers to engage in a much-needed discourse about this worrisome phenomenon.

Politicians and law enforcement officials have advocated the militarization of local law enforcement on the grounds that it promotes public and officer safety, and some early research seemingly supported those claims. Two new studies reveal limitations in the data used in this prior work. When these issues are addressed, evidence for the benefits of militarization largely vanishes.

To contain the COVID-19 pandemic, many countries around the world rushed to develop digital contact tracing apps. However, the low rates of app installation have undermined the efficacy of such tools. A study by Munzert et al. shines light on potential barriers to adoption, as well as levers that could be used to increase uptake.

Horien and colleagues provide a roadmap to working with large, publically available imaging datasets.

Studies of transfers of surplus military equipment to police have argued that they reduce crime. Gunderson et al. reanalysed US federal data and replicated key studies. They find no credible evidence that crime drops when local police get more SME.

Lowande shows that existing estimates of the effect of police militarization in the United States are based on incomplete data. When military surplus was recalled from local police, there were negligible or undetectable impacts on violent crime and officer safety.

In their study of Chinese consumers, Salvo et al. find that demand for food delivery—and the generation of plastic waste—rises when ambient air quality is poor.

Controlled used of fire is one of the most outstanding achievements attributed to humankind. Artificial intelligence estimates the heating temperatures of flint tools fabricated by hominins over 300,000 years ago at Qesem Cave, providing insightful views into both advanced behaviours and the cognitive evolution of our species.

During the COVID-19 pandemic, suicide rates in Japan declined by 14% during the initial wave (February to June 2020) but increased by 16% in the second wave (July to October 2020), with a larger increase (37%) among females.

Integrating human mobility and activity data with ground-level measurements and air quality models, Shen et al. find that despite a reduction in outdoor PM_2.5 during the COVID-19 quarantine in China, overall population exposure to PM_2.5 increased.

Combining mobile tracking data and a survey experiment, Munzert et al. show that Germany’s contact tracing app is underused by those who socially distance less; however, even small cash incentives increased app uptake in the cohort.

Infants listened to lullabies and other songs recorded in cultures and languages that were unfamiliar to them. They relaxed more in response to the lullabies. This suggests that infants may be predisposed to respond to common features of lullabies.

Vosberg et al. have developed a continuous measure of biological sex in an adolescent cohort, based on quantitative traits of the brain and body. Within each sex, these ‘sex scores’ are associated with sex hormones and personality traits.

Do human confidence judgments follow Bayesian principles? Using a task in which confidence is not reported on a scale but used to inform decisions, Lisi et al. find that behaviour is better explained by discrete confidence levels than Bayesian probability.

The genetic variance that predicts educational attainment or intelligence test performance predicts individual-level voter turnout in a nationally representative sample and among people with psychiatric conditions, such as depression.