Faces in the crowd:Twitter as alternative to protest surveys

Who goes to protests? To answer this question, existing research has relied either on retrospective surveys of populations or in-protest surveys of participants. Both techniques are prohibitively costly and face logistical and methodological constraints. In this article, we investigate the possibility of surveying protests using Twitter. We propose two techniques for sampling protestors on the ground from digital traces and estimate the demographic and ideological composition of ten protestor crowds using multidimensional scaling and machine-learning techniques. We test the accuracy of our estimates by comparing to two in-protest surveys from the 2017 Women’s March in Washington, D.C. Results show that our Twitter sampling techniques are superior to hashtag sampling alone. They also approximate the ideology and gender distributions derived from on-the-ground surveys, albeit with some bias, but fail to retrieve accurate age group estimates. We conclude that online samples are yet unable to provide reliable representative samples of offline protest

Kingdom of trolls? Influence operations in the Saudi Twittersphere

Saudi Arabia has one of the highest rates of Twitter penetration in the world. Despite high levels of repression, the platform is frequently used to discuss political topics. Recent disclosures from Twitter have revealed state-backed attempts at distorting the online information environment through influence operations (IOs). A growing body of research has investigated online disinformation and foreign-sponsored IOs in the English-speaking world; but comparatively little is known about online disinformation in other contexts or about the domestic use of IOs. Using public releases of IO tweets, we investigate the extent of such activity in Saudi Arabia. Benchmarking these tweets to four samples of Saudi Twitter users, we find that engagement with IO accounts was lower than engagement with the average user, but equal to engagement with news accounts. Network analysis reveals that engagement with IO accounts was largely driven by a small number of influential accounts

Behavioural modification of local hydrodynamics by asteroids enhances reproductive success

The reproduction of apex species, such as sea stars, is important for sustaining many marine ecosystems. Many sea star species reproduce externally, introducing gametes in the turbulent benthic boundary layer. Sea stars often aggregate and adopt characteristic behaviour, such as arched posturing, while spawning. Here we quantify, for the first time, the hydrodynamic advantages of postural changes and the extent to which they enhance the efficiency of external reproduction. Hydrodynamic and fertilisation kinetic theoretical modelling were used to provide context and comparison. The arched posture was clearly important in the downstream advection of gametes. Digital particle image velocimetry, acoustic doppler velocimetry and dye release experiments indicated reduced wake and lower shear stresses downstream of arched sea stars, which increased downstream transport of gametes compared to those in the flat position. In all cases, sperm concentration decay rates of two orders-of-magnitude over distances < 20 cm were inferred from fluorometry, confirming the requirement for close aggregation. The level of turbulence and hence downstream gamete dilution was increased by greater current speeds and a rougher seabed. Both an arched posture and hydrodynamic conditions may improve external reproduction efficiency, with behavioural mechanisms providing the primary contribution

Burnings, beatings, and bombings:Disaggregating anti-Christian violence in Egypt, 2013-2018

What are the determinants of ethnic violence? Existing research has forwarded a range of often competing explanations, from political opportunism to economic competition to state incapacity. We argue that this diversity of accounts is attributable, in part, to scholars' tendency to lump together distinct forms of ethnic violence that have different underlying determinants. We propose that scholars instead disaggregate ethnic violence and put forward a typology based on the target of the attack (properties vs. individuals) and whether assailants use arms. We demonstrate the utility of this typology by applying it to an original dataset of ethnic attacks against Christians in Egypt from 2013 to 2018. In addition to a set of shared factors, we find that unarmed attacks against property (burnings) are the product of political mobilization, unarmed attacks against individuals (beatings) are related to socioeconomic tensions, and armed attacks (bombings) follow the strategic logic of terrorist violence.</p

Did local civil rights protest liberalize whites’ racial attitudes?

Mazumder investigates the long-term effect of protest on political attitudes. He finds that whites have more liberal views on race and are more likely to be Democrats in counties where Civil Rights protest was reported in the early 1960s. The analysis omits a crucial predictor of protest and of racial attitudes: college education. We include the proportion of adults with a college degree and the number of college students at the county level. The inclusion of these variables, along with some other contextual variables from the original dataset, cuts the effect of protest by about half. Protest is no longer statistically significant in eight out of nine combinations of outcome variables and protest measures. The size of the effect remains trivial when we shift analysis from the county to the individual level. Even accounting for the individual’s own education, the county’s proportion of college graduates is strongly associated with racial liberalism. This finding emphasizes the importance of education as a contextual variable. Our conclusion highlights two methodological lessons. First, causal inference should be paired with sustained historical inquiry that specifies plausible mechanisms. Second, statistical tests for sensitivity can induce complacency about the risk of confounding