Tom Postmes

Tom Postmes
University of Groningen | RUG · Department of Psychology

PhD 1997 (University of Amsterdam)

About

240
Publications
371,032
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21,314
Citations
Citations since 2017
29 Research Items
10352 Citations
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201720182019202020212022202305001,0001,500

Publications

Publications (240)
Chapter
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This chapter provides an overview of the SIDE model, its theoretical roots and how it developed, and its utility in explaining a range of social influence and other group phenomena as instantiated within the new communications technologies. As a model grounded in the social identity approach the SIDE model provides broad scope for analyzing how spe...
Book
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Protesten, demonstraties, rellen en onlusten zijn allen uitingen van sociale onrust. Hoe ontstaat deze onrust? Is onrust in de 21ste eeuw wezenlijk aan het veranderen? En wat is de kans dat rellen zoals in Parijs (2005), Londen (2011) of Griekenland en Spanje (2010-2012) ook in Nederland plaatsvinden? Op basis van 4 casestudies en een literatuurove...
Article
This paper introduces a single-item social identification measure (SISI) that involves rating one's agreement with the statement 'I identify with my group (or category)' followed by a 7-point scale. Three studies provide evidence of the validity (convergent, divergent, and test-retest) of SISI with a broad range of social groups. Overall, the estim...
Article
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The present paper tries to overcome the dualism of group-level vs. individualistic analysis of small group processes, by presenting a model of social identity formation that incorporates factors at both levels of analysis as well as their interaction. On the basis of prior theorising in the social identity tradition and a programme of research span...
Article
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Online discussions about controversial topics seem more prone to misunderstanding and even polarization than similar discussions held face-to-face. Recent research uncovered an important reason why: certain behaviors that are used to communicate diplomacy and tact in face-to-face discussions – specifically, responsiveness and ambiguity – are more d...
Preprint
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Discussions on social media have been considered a contributing factor to the increasing polarization the Western world is witnessing. In this study, we use automated and manual coding to analyze diplomatic behavior in online discussions and its consequences for polarization dynamics. We analyze Reddit forums with differing norms: reddits known for...
Article
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Social relationships are important predictors of a range of individual outcomes, such as wellbeing and health. These social relationships are conceptualised in different ways, such as (inter-personal) forms of social support , identification with groups, or social capital . What is the overlap among these concepts and in what ways do they differ? T...
Preprint
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Feeling heard is seen as a cornerstone of intimate relationships and healthy self-development. In public life, feeling heard may play an important role in a well-functioning representative democracy. The current paper aimed to define and measure feeling heard in the context of everyday interpersonal interactions. Based on an integrative literature...
Article
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Objectives: To evaluate the long-term (psychosomatic) health consequences of man-made earthquakes compared with a non-exposure control group. Exposure was hypothesised to have an increasingly negative impact on health outcomes over time. Setting: Large-scale gas extraction in the Netherlands causing earthquakes and considerable damage. Particip...
Article
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In online text-based discussions, people behave less diplomatically because they are more outspoken and less responsive. This can feed impressions of polarization. This article uses a new methodology to isolate the influence of outspokenness and responsiveness in shaping perceptions of polarization in online chat and face-to-face discussions. Text-...
Article
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In group discussions, people rely on everyday diplomatic skills to socially regulate the interaction, maintain harmony, and avoid escalation. This article compares social regulation in online and face-to-face (FtF) groups. It studies the micro-dynamics of online social interactions in response to disagreements. Thirty-two triads discussed, in a rep...
Article
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In many Western societies there are rising concerns about increasing polarization in public debate. However, statistics on private attitudes paint a different picture: the average attitudes in societies are more moderate and remain rather stable over time. The present paper presents an agent-based model of how such discrepancies between public opin...
Article
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Even when overt sexism and prejudice become rarer, social norms that perpetuate inequality are remarkably persistent. The present research lays out one of the subtle ways in which sexist norms may spread through society, by pointing to the role of responses to sexism. We investigate how third parties infer social norms about sexism when observing s...
Article
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This study explores how people navigate the field of tension between expressing disagreement and maintaining social relationships in text-based online as compared to face-to-face discussions. In face-to-face discussions, differences of opinion are socially regulated by introducing ambiguity in message content coupled with instant responding on a re...
Article
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We review online activism and its relations with offline collective action. Social media facilitate online activism, particularly by documenting and collating individual experiences, community building, norm formation, and development of shared realities. In theory, online activism could hinder offline protests, but empirical evidence for slacktivi...
Article
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Do people signal protest by bringing out a protest vote when they feel they have been collectively disadvantaged? Political scientists have been interested in “protest voting” yet theoretical understanding is limited. Social psychologists have studied other forms of collective protest extensively. The present study integrates insights from the poli...
Article
The present research examined from a normative perspective how intragroup normative processes regulate the consequences of the linguistic intragroup bias (LIB). Results of three studies supported our hypothesis that intragroup approval of an ingroup member who uses the LIB plays a key role in perpetuating pro‐ingroup bias. In Study 1, ingroup membe...
Article
When someone expresses a morally deviant opinion, this person is likely to face derogation by their group. We examined whether people reacted more positively to opinion deviance when social identity was induced from individual expressions, rather than deduced from ingroup similarities. Participants (n = 155 divided over 41 groups) engaged in small-...
Article
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What are the cultural origins of societal conflicts that revolve around democratization, women's rights, and modern libertarian values? We propose that deep‐seated differences in community‐based collective values (at the micro‐level) may be related to why people support anti‐government protest and why they support repression of such protests (at th...
Book
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Gas extraction in the province of Groningen has been a true moneymaker for The Netherlands yet it has also been evoking human-induced earthquakes for years. Added together, the successions of earthquakes have resulted in considerable damage - hence dubbed a "disaster in slow motion" . This report presents a series of studies on societal unrest and...
Article
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Group growth is of fundamental importance to understanding social influence. How do passive bystanders become psychologically involved when observing a small group of actors? Our hypothesis was that the kind of solidarity displayed by the group shapes the bonds that emerge with an audience. We studied audience responses to modern dance performances...
Article
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While injustice is widespread, collective action against it appears to be rare. This paper argues that this may be because research often focuses on a narrow range of outgroup‐oriented actions, such as demonstrating, signing petitions, that are symbolic of a collective response to injustice. The present work takes a bottom‐up approach to study a br...
Article
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This work examines the hypothesis that older workers’ responses to negative events at work depend, in part, on daily fluctuations of subjective age bias (SAB; how old people feel compared to their actual age) and age group identification (age GI). We tested whether SAB and age GI fluctuate over time, whether they influence attributions of negative...
Article
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A meta‐analysis of 76 studies (N = 31,016) examined the relationship between social identification and depression. Overall, individuals who identify highly with a group tend to report less depression (average rz = ‐.15). However, a large amount of variability between studies was observed. The 95% prediction interval, which indicates the true effect...
Article
Based on the interactive model of identity formation (Postmes, Haslam, & Swaab, 2005) we investigate whether displays of coordinated actions foster feelings of solidarity. Participants were randomly assigned to roles of actors and observers in two experiments (N = 191 and 276). Actors performed in an “airband” in which all played air-guitar (enacti...
Article
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Integrating the social identity and aging literatures, this work tested the hypothesis that there are two independent, but simultaneous, responses by which adults transitioning into old age can buffer themselves against age discrimination: an individual response, which entails adopting a younger subjective age when facing discrimination, and a coll...
Article
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Culture shapes individuals, but the measurement of cultural differences has proven a challenge. Traditional measures of cultural values focus on individual perceptions. We suggest that values are established and maintained within social communities of proximate others, such as the family and its social environment. Within such communities, values s...
Article
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In recent years, extreme right-wing and left-wing political parties and actors have gained popularity in many Western countries. What motivates people to vote for extreme right- or left-wing parties? In previous research, we showed that a collectively shared sense of doom and gloom about society can exist among citizens who, individually, experienc...
Article
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The perceived possibility of movement between groups, referred to as permeability of group boundaries, is considered a key factor in explaining intergroup relations. However, so far, permeability has been conceptualized in different ways and there exists no validated measure. Integrating different conceptualizations, we developed a scale distinguis...
Article
Increasing outgroup empathy is an important first step toward reducing intergroup conflict. The communication of group-based anger has been found to increase outgroup empathy due to its presumed relational function (as it signals to the outgroup that they unfairly treat the ingroup, but also that the ingroup wants to maintain a positive intergroup...
Article
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It is well known that politicized identities are especially good predictors of collective action, but very little is known about what these identities are. We propose that moral identity content plays a central role in politicized identities. We examined this among (un)politicized Americans in the 2012 US Presidential Elections. In a longitudinal c...
Article
Strong social identity does not lead to lack of accountability and “bad” behavior in groups and crowds but rather causes group behavior to be driven by group norms. The solution to problematic group behavior is therefore not to individualize the group but rather to change group norms, as underlined by the relational dynamics widely studied in the S...
Article
Deindividuation is a characteristic of the individual in the crowd. It is a psychological state of decreased self-evaluation, causing antinormative and disinhibited behavior. The impact of deindividuation theory in science and society (especially twentieth-century politics) makes it one of social science's more influential contributions. Deindividu...
Article
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It can be hard for individuals to manage multiple group identities within their self-concept (e.g., being a Christian and a woman). We examine how the inter-identity fit between potentially conflicting identities can become more harmonious through a self-defining group philosophy for life. Specifically, we test the hypothesis that holistic group id...
Data
The theoretical and methodological distinction between self-definingness and identification. This appendix outlines the theoretical distinction between identification and self-definingness, discusses Pilot bivariate correlations between identification and self-definingness and reports a factor analysis of identification and self-definingness. (DOCX...
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Holisticness, Self-definingness and inter-identity fit items. (DOCX)
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Hypothesis notes. A more detailed discussion about expectations concerning groups low in holisticness. (DOCX)
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Sample composition. Discussing the inclusion of non-religious individuals in the sample. (DOCX)
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Factor analysis of holisticness and self-definingness. (DOCX)
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Study 2 methodology notes. Discussing the inclusion of the self in the RT task. (DOCX)
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Semantic Networks Analysis: Methodological Notes. Appendix including additional notes on Study 3 method and results. Method notes discuss the use of a median split in network construction, the window size used to code ties (relations) between nodes (identity concepts), and notes on data cleaning and coding. Results notes discuss the Figures, negati...
Article
Individuals often cannot address (objective) group injustices until they develop a (subjective) critical awareness of them. In three studies, we tested two potential psychological pathways toward critical awareness: Reflection (deductive, knowledge driven) and action (inductive, action driven) mindsets. Across studies, participants were exposed to...
Article
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New approaches in cultural psychology are conceiving culture as a dynamic social process, structured intersubjectively. This paper highlights the importance and benefits of such an approach. We point out that to do justice to this, we need a shift in who and what we study. A dynamic and intersubjective approach needs to go beyond studying “the self...
Article
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Previous research has shown that negative attitudes towards immigrants and support for anti-immigrant parties are observed both among those experiencing relative deprivation and those experiencing relative gratification (so called v-curve). Whereas the effect of relative deprivation is intuitive, the effect of relative gratification is more difficu...
Article
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Over the last decade, several countries around the world developed a collective sense of doom and gloom: Their Zeitgeist could be characterized as one of decline. Paradoxically, in some countries, such as the Netherlands, this collective discontent with society seems to exist despite high levels of individual well-being. Current psychological resea...
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Two experiments investigated the role of intragroup communication in intergroup conflict (de-)escalation. Experiment 1 examined the effects of intragroup communication (vs. individual thought) and anticipated face-to-face intergroup contact (vs. no anticipated face-to-face intergroup contact). The group discussions of stigmatized group members who...
Article
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We examine how different forms of co-action give rise to feelings of solidarity. We propose that (a) coordinated action elicits a sense of solidarity, and (b) the process through which such solidarity emerges differs for different forms of co-action. We suggest that whether solidarity within groups emerges from uniform action (e.g. synchronizing, a...
Article
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Two experiments investigated when perceivers can construe stereotype-inconsistent information abstractly (i.e., interpret observations as generalizable) and whether stereotype-consistency delimits the positive relation between abstract construal level and stereotyping. Participants (N1=104, N2=83) prepared for intragroup communication or formed an...
Article
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The purpose of this research was to meta-analyze studies which experimentally induced an achievement goal state to examine its causal effect on the individual’s performance at the task at hand, and to investigate the moderator effects of feedback anticipation and time pressure. The data set comprised 19 papers, 79 individual effect sizes, and 3,482...
Article
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People's Belief in a Just World (BJW) plays an important role in coping with misfortune and unfairness. This paper demonstrates that understanding of the BJW concept, and its consequences for behavior, is enhanced if we specify what (or who) the source of justice might be. We introduce a new scale, the 5-Dimensional Belief in a Just Treatment Scale...
Article
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A minority of the public are sceptical about the idea that humans cause climate change. This has received a lot of attention in the media as well as in scientific research. Many became concerned when scepticism—a marginal phenomenon in many countries across the globe—increased in the US and a few other (mainly Anglophone) countries towards the end...
Article
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Research on in-group identification typically focuses on differences in individuals’ identification at the individual level of analysis. We take a multilevel approach, examining the emergence of group influence on identification in newly formed groups. In three studies, multilevel confirmatory factor analysis confirmed two dimensions of identificat...
Article
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We investigated U.S. citizens' politicization (i.e., switching from not self-defining to self-defining as an active political party supporter) during the 2012 U.S. Presidential Elections. We used a novel identity content approach to explore qualitative changes in overlap between personal and politicized identity traits. We collected longitudinal da...
Article
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Social interaction is pivotal to the formation of social relationships and groups. Much is known about the importance of interaction content (e.g., the transfer of information). The present review concentrates on the influence of the act of conversing on the emergence of a sense of solidarity, more or less independently of the content. Micro-charac...
Article
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Conversations are susceptible to many disturbances: A speaker's hesitations, distractions, or, when communicating online, technical hiccups that may cause brief delays. Research among previously unacquainted individuals revealed that brief disruptions in conversational flow can have profound social consequences: Silences or delays in mediated commu...
Article
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Principles of lean office management increasingly call for space to be stripped of extraneous decorations so that it can flexibly accommodate changing numbers of people and different office functions within the same area. Yet this practice is at odds with evidence that office workers' quality of life can be enriched by office landscaping that invol...
Article
Is democracy really a good thing because it improves well-being? Everywhere? Here we use multiple regression analysis to examine continuous associations between democracy and well-being across 137 countries. The results are clarified by breaking them down for 20 poor countries with demanding winters or summers (threatening habitats), 48 poor countr...
Article
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This research examines how technology usage can instigate social change in a developing country. We expected that technology usage leads to changes in modern cultural values and attitudes toward gender equality while traditional values persist. This was tested in an information and communication technology (ICT) for Development Aid project among Et...
Conference Paper
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Our social dynamic conceptualization of culture sees social values as established by social relationships (e.g., one’s community). Our scale, that distinguishes four processes both at the individual and community-level, differentiates between cultural groups and provides new insights into cultural processes.
Conference Paper
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Cultural differences are often studied in the context of a dichotomy between “Western” and “Eastern” cultures. The present research re-conceptualizes the cultural process beyond this dichotomy, taking a social dynamic approach that studies relations within different social communities and their individual members. On the basis of this approach...
Article
More than an expression of individuality, creativity takes shape in a social context
Article
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During the past three decades, the achievement goal approach to achievement motivation has emerged as an influential area of research, and is dedicated to understanding the reasons behind the individual's drive to achieve competence and performance. However, the current literature on achievement goals is segmented rather than integrated. That is, c...
Article
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In 2 meta-analyses, we examined the relationship between perceived discrimination and psychological well-being and tested a number of moderators of that relationship. In Meta-Analysis 1 (328 independent effect sizes, N = 144,246), we examined correlational data measuring both perceived discrimination and psychological well-being (e.g., self-esteem,...
Article
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To date, the study of societal change in social and political psychology has been dominated by an intergroup relations research agenda. But in addition to intergroup dynamics, there are other major pathways to societal change and emancipation, which are almost never systematically considered in psychological research. The distribution of technologi...
Data
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This short note was written as an addendum to Postmes, Haslam, & Jans (in press). We developed a reliable and short way to assess identification. SISI is a measure of social identification, defined as the positive emotional valuation of the relationship between self and ingroup. SISI has considerable overlap with Leach et al. (2008)’s measure of se...