Given rising antiimmigrant sentiment in the United States, it is increasingly important to further investigate which psychological factors may facilitate helping toward immigrants. In two studies with White Americans (total N = 1,139), we investigated whether (and when) two positive emotions—group-based gratitude and group-based pride—influence benevolent and activism support toward immigrants in the United States. Although previous research on individual-level gratitude and pride suggests that they are distinct emotions, at the group-level, we find that among White Americans, national gratitude and pride clustered together and were statistically indistinguishable. Importantly, this combination of American gratitude-plus-pride had differential effects on helping toward immigrants, depending on two key factors: Political orientation of the perceiver, and the type of support rendered. Among conservatives and moderates, American gratitude-plus-pride was predictive of increased benevolent support. However among liberals, it was related to decreased activism support. Our findings suggest that the impact of group-based gratitude and pride on helping toward immigrants is complex, and contingent upon preexisting dispositions.

Grievances about being a man have surged in recent years, with men's rights activists claiming that men are unjustly disadvantaged relative to women. Group-based relative deprivation may explain such perceptions. Across one correlational study among White American men (N = 195) and one experimental study among Black and White American men (N = 492), we examined whether low trait modesty may explain why some men experience group-based relative deprivation, and endorse normative and non-normative men's rights activism. Across both studies, there were significant negative direct and indirect effects of trait modesty on men's rights activism. Specifically, trait modesty negatively predicted endorsement of normative and non-normative men's rights activism, and these effects were mediated by lower group-based relative deprivation. These findings advance our understanding of how personality traits shape perceptions of group-based disadvantage and collective action in defence of men's rights.

Although social scientists have studied group-based relative deprivation (GRD) for more than half a century, there is no established, validated scale for measuring GRD. We developed the GRD scale, which can be administered in different intergroup contexts, and examined its psychometric properties in two samples (ns = 334 & 309), its construct validity in two experimental studies (ns = 98 & 271), and its convergent validity in a correlational study (n = 189). Analyses based on Classical Test Theory showed that the scale has high internal consistency, converging on similar estimates across several different internal consistency coefficients (⍺, ⍵_t, ⍵_h), and demonstrating excellent goodness-of-fit indices. Using Item-Response Theory approaches, Mokken scaling analysis showed that the scale is unidimensional and strong. The scale also differentiated between relevant groups (GRD scores were higher among women than men). Importantly, we demonstrated the construct validity of the scale (as conceptualized by Borsboom et al., 2004) by showing that objective group-based disadvantage in tangible, monetary terms is causally related to scores on the GRD scale. Finally, we demonstrated the scale’s convergent validity.

Collective action is often equated with progressive politics, but are there aspects of group mobilisations that generalise across contexts? We examine general social and personality psychological factors behind endorsement of group-based violence across different types of violent group mobilisation. Specifically, we focus on the endorsement of group-based violence amongst supporters of the Black Lives Matter (BLM) movement (N = 394), an immigration-critical group (N = 252), and soccer supporters (N = 445). Across three preregistered studies, we tested an integrative model including personality and social psychological factors. Several effects were consistent across all three contexts, with group-based relative deprivation positively, and honesty-humility negatively, predicting support for violence. Further, amongst BLM supporters and the immigration-critical group, emotionality negatively predicted support for violence, violent intentions, and self-reported aggression/violence. Overall, our results suggest that individuals who endorse violence in different contexts have some psychological factors in common.

There is growing recognition that members of structurally advantaged groups experience group-based relative deprivation. We consider the idea that personality may explain these “entitlement-based” feelings of deprivation. Specifically, we predicted that modesty would be negatively associated with group-based relative deprivation among members of advantaged groups, but not amongst disadvantaged groups. Two studies focusing on White and Black Americans (N = 334), and Men and Women (N = 309) showed that modesty interacted with group membership. Modesty was negatively related to group-based relative deprivation amongst White Americans and men, but not amongst Black Americans and women. The findings help explain why some individuals espouse rhetoric that their group is being disfavored, even when group statistics and history suggest otherwise.

Violent extremism is a costly, global problem, yet research has yet to come to a consensus on the psychological underpinnings of violent extremism. The aim of this dissertation was to contribute to a more nuanced understanding of the psychological underpinnings of violent extremism and group-based violence by (1): moving beyond the traditional focus on disadvantaged groups, Islamist extremism, and first-hand experience of victimisation or disadvantage; (2): moving past the long-standing person-situation dichotomy; and (3) attempting to integrate the role of personality and social psychological factors in susceptibility to violent extremism.

In Study I we tested a social psychological model of Islamist extremism amongst Muslims living in the West, and Muslims living in countries which have first-hand experience of Western military intervention. We found that the model applies across contexts, suggesting that a sense of muslim identity based on a sense of victimisation, cuts across borders, and victimisation can be experienced vicariously.

In Study II I found that both personality (honesty-humility) and team identification predict violent intentions amongst soccer supporters, and that collective narcissism partially mediated these associations. 

Study III identified common personality and social psychological predictors of group-based violence across three studies sampling from Black Lives Matters supporters, an immigration-critical group (Swedes), and soccer supporters. Across all contexts, with group-based relative deprivation positively and honesty-humility negatively predicting support for violence. Further, amongst BLM supporters and the immigration-critical group, emotionality negatively predicted support for violence, violent intentions, and self-reported aggression/violence. 

In Study IV I predicted that modesty would be negatively associated with group-based relative deprivation amongst members of advantaged but not disadvantaged groups. Across two studies amongst White and Black Americans, and amongst men and women, I found that modesty interacted with group membership. Specifically, modesty was negatively related to group-based relative deprivation amongst White Americans but not Black Americans, and amongst men, but not women. An implication of these findings is that individuals espousing the rhetoric of far-right and men’s right’s movements, are low in modesty, predisposing them to feel a greater sense of entitlement, and hence violation of entitlement.

Overall, the findings across these studies suggest that both personality and social psychological variables need to be considered when examining why individuals endorse violent extremism. Furthermore, the findings demonstrate that there are common personality and social psychological factors underpinning different forms of group-based violence, including identity processes, feelings of group-based disadvantage and injustice, and personality characterised by low honesty-humility and emotionality.

Furthermore, feelings of injustice and group-based relative deprivation can be experienced in the absence of direct experience of victimisation, in non-political contexts, and even when one belongs to a structurally advantaged group. Although many groups perceive that their group is disadvantaged relative to other groups, personality (e.g., low modesty) may predispose members of structurally advantaged groups to perceive that their group is not getting what they are entitled to.

Soccer supporter violence remains a persistent global problem. The majority of research examining the psychological underpinnings of soccer supporter violence have focused primarily on the role of team identification. Relatively little research has examined the role of basic personality traits and willingness to engage in violence amongst soccer supporters. In a study amongst Swedish soccer supporters (N = 247), we examined whether honesty-humility and team identification predict violent behavioral intentions; examining if collective narcissism mediates these associations. Honesty-humility negatively predicted violent intentions, and team identification predicted violent intentions. Collective narcissism partially mediated these associations. When both Honesty-humility and team identification are accounted for though, collective narcissism did not predict violent intentions. Such findings have implications for the design of violence prevention interventions amongst soccer supporters.

Cognitive aging creates major individual and societal burden, motivating search for treatment and preventive care strategies. Behavioural interventions can improve cognitive performance in older age, but effects are small. Basic research has implicated dopaminergic signalling in plasticity. We investigated whether supplementation with the dopamine-precursor L-dopa improves effects of cognitive training on performance. Sixty-three participants for this randomised, parallel-group, double-blind, placebo-controlled trial were recruited via newspaper advertisements. Inclusion criteria were: age of 65–75 years, Mini-Mental State Examination score >25, absence of serious medical conditions. Eligible subjects were randomly allocated to either receive 100/25 mg L-dopa/benserazide (n = 32) or placebo (n = 31) prior to each of twenty cognitive training sessions administered during a four-week period. Participants and staff were blinded to group assignment. Primary outcomes were latent variables of spatial and verbal fluid intelligence. Compared to the placebo group, subjects receiving L-dopa improved less in spatial intelligence (−0.267 SDs; 95%CI [−0.498, −0.036]; p = 0.024). Change in verbal intelligence did not significantly differ between the groups (−0.081 SDs, 95%CI [−0.242, 0.080]; p = 0.323). Subjects receiving L-dopa also progressed slower through the training and the groups displayed differential volumetric changes in the midbrain. No statistically significant differences were found for the secondary cognitive outcomes. Adverse events occurred for 10 (31%) and 7 (23%) participants in the active and control groups, correspondingly. The results speak against early pharmacological interventions in older healthy adults to improve broader cognitive functions by targeting the dopaminergic system and provide no support for learning-enhancing properties of L-dopa supplements in the healthy elderly. The findings warrant closer investigation about the cognitive effects of early dopamine-replacement therapy in neurological disorders. This trial was preregistered at the European Clinical Trial Registry, EudraCT#2016-000891-54 (2016-10-05).

Human and non-human animal research converge to suggest that the sense of smell, olfaction, has a high level of plasticity and is intimately associated with visual-spatial orientation and memory encoding networks. We investigated whether olfactory memory (OM) training would lead to transfer to an untrained visual memory (VM) task, as well as untrained olfactory tasks. We devised a memory intervention to compare transfer effects generated by olfactory and non-olfactory (visual) memory training. Adult participants were randomly assigned to daily memory training for about 40 days with either olfactory or visual tasks that had a similar difficulty level. Results showed that while visual training did not produce transfer to the OM task, olfactory training produced transfer to the untrained VM task. Olfactory training also improved participants’ performance on odor discrimination and naming tasks, such that they reached the same performance level as a high-performing group of wine professionals. Our results indicate that the olfactory system is highly responsive to training, and we speculate that the sense of smell may facilitate transfer of learning to other sensory domains. Further research is however needed in order to replicate and extend our findings.

Suicide terrorism, which is usually tied to a non-state organization, is the act of sacrificing one’s life in an effort to harm, damage, or destroy members of an out-group, for political and social objectives.