People donate billions each year, yet giving is often ineffective. Over five experiments, Burum and colleagues tested an explanation for inefficient giving based on evolutionary game theory, ruling out alternative accounts based on cognitive or emotional limitations.

See Burum et al.

The natural world is full of objects that we have no difficulty identifying, thinking and communicating about. How is this diversity of objects represented in the human mind? Hebart et al. use empirical and computational methods to show that people share mental representations of objects based on a small number of dimensions.

See Hebart et al.

See also News & Views by Riesenhuber

Although new technologies have made it easier for businesses to connect globally, international business travel has grown at a tremendous pace. Coscia et al. use a large dataset of business travel to show that it helps to diffuse knowledge: before they become competitive in new industries, countries receive visitors from places where that industry already thrives.

See Coscia et al.

Complex culture isn’t uniquely human. By sampling 39 chimpanzee populations across the African continent, Boesch et al. find that chimpanzees possess a highly diverse culture of termite fishing that differs strongly among groups. Individuals copy group-specific techniques and their combinations with high conformity to maintain a unique group culture.

See Boesch et al.

See also News & Views by Koops

Using large-scale data, Kraemer et al. find that human mobility patterns vary across the globe and in scale by environmental and sociodemographic contexts. There are tenfold differences in mobility patterns depending on the countries’ economic development.

See Kraemer et al.

An analysis of nearly 100 million traffic stops in the US found that police stops and search decisions suffer from persistent racial bias. Black drivers were less likely to be stopped after sunset, when a ‘veil of darkness’ masks one’s race, suggesting racial profiling. Regardless of time of day, the bar for searching Black and Hispanic drivers was lower than that for searching white drivers.

See Pierson et al.

Small, portable artworks have been missing from the archaeological record of the earliest H. sapiens of Southeast Asia–Australasia. New excavations in Sulawesi have uncovered stone engravings depicting the natural world dating back to 26 to 14 kya.

See Langley et al.

Human behaviour shapes the trajectory of pandemics, and behaviour is crucial to curb and contain disease spread. In this Focus, we bring together expert views from a broad range of disciplines across the behavioural and social sciences, to examine how individual and collective behaviour drive and can mitigate the COVID-19 pandemic.

How does the brain support our ability to recognize faces and decipher facial expressions? Wang et al. combine functional and anatomical connectivity data with behavioural measures to create a global model of the human face connectome, proposing a neurocognitive model with three core face-processing streams.

See Wang et al.

Inhabitants of distinct world regions differ in how sharply they distinguish between we-groups and they-groups. Van de Vliert finds that differentiation between in-groups and out-groups co-varies with latitude, but not longitude. Differentiation is highest closer to the equator, and this pattern may be explained by ecological conditions in tropical regions.

See Van de Vliert

The use of single-occupancy vehicles is a primary source of emissions within the control of individuals. Kristal and Whillans report the results of five large-scale field experiments that implemented ‘nudges’ designed to increase carpooling. None of the interventions was successful, highlighting the difficulty of changing commuter behaviour.

See Kristal & Whillans

Despite norms against racial discrimination, there are persistent biases against individuals due to their perceived race. Zhou et al. use multimodal brain imaging to show that the brain engages distinct neural dynamics to sort faces into different racial categories. These neural patterns predict racial biases in facial recognition and altruistic intention.

See Zhou et al.