[6] One of the earliest scientific publications on group processes is The Crowd: A Study of the Popular Mind, written in 1895 by French doctor and scientist Gustave Le Bon.
[7] Subsequent generations of intergroup relations and social influence researchers built from these foundational ideas and explored them through empirical studies.
[6] The empirical study of intergroup relations, as well as the broader field of social psychology, grew tremendously in the years following World War II.
The events of World War II, including the rise of Adolf Hitler and Fascism, the Holocaust, and the widespread use of propaganda, led many social scientists to study intergroup conflict, obedience, conformity, dehumanization, and other related phenomena.
[6] Social scientists were interested in understanding the behavior of the German population under Nazi rule, specifically how their attitudes were influenced by propaganda and how so many could obey orders to carry out or support the mass murder of Jews and other minority groups as part of the Holocaust.
[8] Several prominent social psychologists were directly affected by the Nazi's actions because of their Jewish faith, including Kurt Lewin, Fritz Heider, and Solomon Asch.
[6] The resulting focus on cognitive processes and meaning-making represented a significant shift away from the mainstream behaviorist philosophy that shaped much of psychology research in the first half of the 20th century.
[13] The Civil Rights Movement of the 1950s and 60s led social scientists to study prejudice, discrimination, and collective action in the context of race in America.
In 1952, the NAACP put out a call for social science research to further study these issues in light of the Brown v. Board of Education lawsuit.
[1][15] Subsequent generations of scientists built on and applied Allport's contact hypothesis to other domains of prejudice including sexism, homophobia, and ableism.
[17] Intergroup relations research in the final decades of the 20th century refined earlier theories and applied insights from the field in real-world settings.
For example, Lee Ross applied his research on correspondence biases and attributional errors in his work on the conflict resolution process in Northern Ireland during The Troubles.
[19][20] One example of this is a recent field study by Betsy Paluck and colleagues, where they used a radio drama infused with positive social norms to increase reconciliation behaviors and attitudes among an entire village in Rwanda.
[22] The advancement of technology has also shaped the study of intergroup relations, first with the adoption of computer software and later with the utilization of neuro-imaging techniques such as fMRI.
[8] One example of psychologists leveraging new technology to advance intergroup relations research is the implicit-association test (IAT), developed by Anthony Greenwald and colleagues in 1998 as a means to measure the strength of implicit (automatic) association of between different mental representations of objects.
[32][33] The Sherifs' Robbers Cave experiment provided evidence for the RCT by arbitrarily assigning boys at a summer camp with similar backgrounds to different groups.
[57] Current research on social inequality has explored the psychological effects of racially disparate policing practices on minorities,[58] whites' tendency to underestimate the pain of blacks due to false beliefs in biological differences,[59] how increasing belonging among students from stigmatized backgrounds can boost their GPAs and retention rates,[60] and how social class influences prosocial behavior.
[62] For example, Judith Harackiewicz and her colleagues examined race and social class as related constructs in a utility-value intervention designed to close the racial achievement gap of underrepresented minority students in introductory STEM college courses.
The theory behind this formula, which emphasizes that context shapes behavior in conjunction with an individual's motivations and beliefs, is a cornerstone of social psychological research.
[15][77] Allport's contributions to the field are still being elaborated upon by psychologists, with one example being the common ingroup identity model developed by John Dovidio and Samuel Gaertner in the 1990s.
[80] These studies have had a lasting impact on the field, providing a theoretical explanation for the origin of intergroup prejudice while also exploring techniques to reduce negative attitudes between groups.
[82] Muzafer Sherif's research on the psychology of group conflict was informed by his experiences observing and studying discrimination and social pressures in the United States and in Turkey.
[88] Asch's research, along with Stanley Milgram's shock experiments, shed light on the psychological processes underlying obedience, conformity, and authority.
[95] Three factors underlie the mechanism of stereotype threat: stress arousal, performance monitoring, and cognitive efforts to reduce negative thoughts and feelings.
[99][100] Steele and his collaborators have studied several forms of interventions to mitigate stereotype threat, including self-affirmation methods and providing psychologically "wise" critical feedback.
[103] Greenwald, who was a student of Gordon Allport, has also investigated in-group favoritism as it relates to discrimination[104] and implicit social bias across a variety of topics including effects on medical school admissions and stereotype formation among young children.
[107] Jennifer Richeson studies racial identity, social inequality, and interracial relations with a focus on understanding the psychological processes behind reactions to diversity.