“…The 31 reports retained for the present systematic review led to the inclusion of 84 studies ( n = 58 cross-sectional, 24 experimental, and 2 longitudinal). The large majority of these reported primary data ( n = 81), while three studies were based on secondary data (Jasko, Grzymala-Moszczynska, et al, 2020, Study 3; Jasko et al, 2017; Troian et al, 2019, Study 5). A variety of radical and nonradical, violent and nonviolent, samples from several different countries were investigated: Yellow Vests (France), general population (Canada, Spain, United States, France), undergraduate students (Pakistan, France, United States, Turkey), environmentalists (United States, Poland), nonradical Muslims (Pakistan, Morocco, Indonesia, Spain), far-left extremists (United States, Poland), far-right extremists (United States, United Kingdom), feminists (Poland), former members of the Liberation Tigers of Tamil Eelam (Sri Lanka), animal rights activists (United States), and French-Maghrebi (France), to name a few.…”