How do state and protester violence affect whether protests grow or shrink? Previous research finds conflicting results for how violence affects protest dynamics. This article argues that expectations and emotions should generate an n-shaped relationship between the severity of state repression and changes in protest size the next day. Protester violence should reduce the appeal of protesting and increase the expected cost of protesting, decreasing subsequent protest size. Since testing this argument requires precise measurements, a pipeline is built that applies convolutional neural networks to images shared in geolocated tweets. Continuously valued estimates of state and protester violence are generated per city-day for 24 cities across five countries, as are estimates of protest size and the age and gender of protesters. The results suggest a solution to the repression-dissent puzzle and join a growing body of research benefiting from the use of social media to understand subnational conflict.

Do economic considerations shape attitudes toward immigration? In this article, we consider the relationship between economic interests and immigration preferences by examining how developments in individuals' sectors of employment affect these views. Using survey data across European countries from 2002 to 2009 and employing new measures of industry-level exposure to immigration, we find that sectoral economies shape opinions about immigration. Individuals employed in growing sectors are more likely to support immigration than are those employed in shrinking sectors. Moreover, the economic context matters: Making use of the exogenous shock to national economies represented by the 2008 financial crisis, we show that sector-level inflows of immigrant workers have little effect on preferences when economies are expanding, but that they dampen support for immigration when economic conditions deteriorate and confidence in the economy declines. These sectoral effects remain even when controlling for natives' views about the impact of immigration on the national economy and culture. When evaluating immigration policy, individuals thus appear to take into account whether their sector of employment benefits economically from immigration.

Scholars in many fields have long noted the importance of social context in the development of political ideology. Recent work suggests that political ideology also has a heritable component, but no specific gene variant or combination of variants associated with political ideology have so far been identified. Here, we hypothesize that individuals with a genetic predisposition toward seeking out new experiences will tend to be more liberal, but only if they are embedded in a social context that provides them with multiple points of view. Using data from the National Longitudinal Study of Adolescent Health, we test this hypothesis by investigating an association between self-reported political ideology and the 7R variant of the dopamine receptor D4 gene (DRD4), which has previously been associated with novelty seeking. Among those with DRD4-7R, we find that the number of friendships a person has in adolescence is significantly associated with liberal political ideology. Among those without the gene variant, there is no association. This is the first study to elaborate a specific gene-environment interaction that contributes to ideological self-identification, and it highlights the importance of incorporating both nature and nurture into the study of political preferences.

Physical and mental health is known to have wide influence over most aspects of social life-be it schooling and employment or marriage and broader social engagement-but has received limited attention in explaining different forms of political participation. We analyze a unique dataset with a rich array of objective measures of cognitive and physical well-being and two objective measures of political participation, voting and contributing money to campaigns and parties. For voting, each aspect of health has a powerful effect on par with traditional predictors of participation such as education. In contrast, health has little to no effect on making campaign contributions. We recommend additional attention to the multifaceted affects of health on different forms of political participation.