The current work presents three studies that examined the role of dehumanization in the association between psychopathy and sexist and violent attitudes towards women. This program had two overarching goals in examining psychopathy, dehumanization, and sexist and violent attitudes towards women. The first goal was to examine whether an indirect association between psychopathy and negative attitudes towards women existed through dehumanization. The second goal was to explore if, by introducing information that humanizes women, levels of dehumanization could be mitigated for individuals high on psychopathic traits. Employing mixed samples for both studies (student and community), Study 1 (n = 514) and Study 2 (n = 202) provided evidence that psychopathy demonstrated an indirect relationship with sexist and violent attitudes towards women via dehumanization. Study 2 also expanded on Study 1 by including a behavioural measure of violent attitudes towards women. Finally, Study 3 (n = 206), again using a mixed sample, attempted to manipulate dehumanization to see if it, and the sexist and violent attitudes associated with it, would be mitigated. Unfortunately, the manipulation failed, but we were able to use the data from Study 3 to provide a replication of the results of Study 2. Across three studies results suggested that the path from psychopathy to negative attitudes towards women was at least partially (if not fully) indirect through dehumanization. This suggests that dehumanization may be an important mechanism to consider when examining the tendency of individuals high in psychopathic traits to engage in violence towards women. Furthermore, because psychopathic traits are associated with violence perpetrated against women, dehumanization could be an important construct to consider when examining potential avenues for clinical interventions. Even more broadly, dehumanization could be an important construct for mitigating the association between psychopathy and violence generally.

The limited research on dreams of the deceased is a cause for concern for those working with bereaved persons. This research addressed four questions: 1. Why do some bereaved individuals dream of the deceased while others do not? 2. Why are some dreams of the deceased a positive experience, while others are negative? 3. Are dreams of the deceased a form of continuing bond? 4. Are continuing bonds helpful for grief recovery? Four studies were conducted. In one, participants were 268 U.S. residents who had a romantic partner or spouse die in the prior 12 to 24 months. The second study had 199 U.S. residents whose dog or cat had died in the prior six months. The third study had 226 U.S. residents who experienced a stillbirth or miscarriage in the prior year. The fourth study had 218 participants, mostly U.S. residents, who had a romantic partner or spouse die in the prior 6 to 24 months. Participants completed all questionnaires online. Study 1 and 2 focused primarily on the issue of predicting the frequency of dreams of the deceased and found that frequency of general dream recall (all dreams, not just dreams of the deceased) was the primary predictor. In addition, grief intensity, openness to experience, and attachment security all showed indirect effects. All four studies, but especially studies 2 through 4, addressed the questions about the quality of dream experience, the relation of dreams of the deceased to continuing bonds, and the adaptiveness of continuing bonds. In general the findings from all four studies, but especially study 4, support the idea that there are multiple types of continuing bonds with differing impacts on grief recovery, and there are differing forms of dreams of the deceased, not all of which represent continuing bonds.

Despite documents such as the United Nations’ Universal Declaration of Human Rights, people still tolerate human rights violations. My dissertation examined possible methods for reducing this toleration. Specifically, I used “hypocrisy induction” to try and reduce toleration of rights violations and encourage pro-human rights responses. Hypocrisy induction—a procedure based on cognitive dissonance—involves having people recognize that their responses in a given situation are at odds with a strongly held attitude. In Study 1, I examined whether people who support human rights would reduce their toleration of a rights violation when confronted with their previous hypocritical toleration. Although participants who were confronted with their hypocrisy were more willing to act to promote human rights, they did not reduce their toleration of a violation, contrary to expectations. One reason for the lack of change in toleration could be that personal toleration of a human rights violation is not directly related to the occurrence of violations. Thus, for Studies 2 and 3, I extended the hypocrisy induction procedure to a case where an ingroup member’s hypocrisy directly resulted in a human rights violation. Specifically, I examined whether Canadians would alter their own toleration of a violation in response to a Canadian official who permitted a human rights violation. Results from both studies indicated that the group-level procedure was effective at encouraging pro-human rights responses, but not at reducing toleration of a violation. Moreover, results from Study 3 indicated that the effect of the group-level procedure was the result of directly-experienced, not vicarious, discomfort. I refer to the dissonance associated with the former type of discomfort as “group-level” dissonance. Although hypocrisy induction was not useful for reducing the toleration of human rights violations, my results suggest that both the group- and individual-level procedures can be used to encourage other pro-human rights responses.

Increasing evidence suggests that bullying may be used by adolescents as a strategic, adaptive tool against weaker peers to obtain valued resources like social status and romantic partners. However, bullying perpetration may only be adaptive within particular environmental contexts that provide opportunities to obtain these resources at minimal costs. These environmental opportunities may be relevant for adolescents who possess particular personality traits and are motivated to exploit these contexts and power imbalances. Using an adaptive social ecological framework, the primary goal of my dissertation was to examine concurrent, longitudinal, and experimental associations between exploitative personality traits and broader social ecologies to facilitate adolescent bullying perpetration. In Study 1, I examined whether risky social environments filtered through antisocial personality traits to facilitate direct and indirect forms of bullying perpetration in a cross-sectional sample of 396 adolescents. In Study 2, I extended Study 1 by investigating the longitudinal associations among bullying, empathic and exploitative personality traits, and social environmental variables, in a sample of 560 adolescents across the first three years of high school. Given that Studies 1 and 2 were correlational, in Study 3, I explored whether bullying perpetration could be experimentally simulated in a laboratory setting through point allocations in the Dictator and Ultimatum economic games by manipulating power imbalances in a sample of 167 first-year undergraduate students. Results from all three studies largely supported the prediction that broader social ecologies filter through exploitative personality styles to associate with bullying perpetration. Exploitative adolescents are primarily likely to take advantage of particular contexts including power advantages, higher social status, and poorer school and neighborhood climates. The results of my dissertation demonstrate the complex reality of the social ecology of bullying, and the need for anti-bullying initiatives to target multiple contexts including individual differences.

The hypothalamic-pituitary-adrenal (HPA) axis regulates the release of stress hormones and its function is dependent on various factors including prior exposure to stressors, circulating gonadal hormones, and developmental status. The overarching goal of this thesis was to uncover the potential mechanisms mediating developmental changes in HPA function and its regulation by gonadal hormones during adolescence and early adulthood. In Chapter 2, I found that pre-pubertal (postnatal day [P]35) and post-pubertal (P45) adolescents responded to an acute stressor with greater release of corticosterone (the main stress hormone in rodents) compared with adults (P75). To determine whether differences in corticosterone release were related to ongoing maturation of HPA feedback, I investigated glucocorticoid receptor (GR) activity and mRNA expression of receptors (Nr3c1, Nr3c2) and their co-chaperones (Fkbp5, Fkbp4, Bag1) in the hippocampus. I provide novel evidence that P35 males have more, not less, GR translocation from the cytosol to the nucleus in response to stress compared with P75 males. Gene expression remained relatively stable across development, except for Fkbp4, which codes for a pro-translocation protein and was up-regulated in P35 males relative to expression in P75 males. Thus, there are developmental shifts in the hormonal response to stress that are likely unrelated to GR activity in the hippocampus. In Chapter 3, I investigated whether differences in HPA function are explained by gonadal status; in adult males, testosterone reduces HPA function. Age-related differences in corticosterone release persisted when orchiectomized (OCX) males at each age were administered testosterone. Moreover, the effect of testosterone changed across the adolescent period; relative to those that got blank implants, testosterone had no effect on post-stress concentrations of corticosterone at P35, increased concentrations at P45, and tended to reduce concentrations at P75. Testosterone reduced expression of AVP in the PVN at all ages, but did not affect Fos (a marker of neuronal activation) expression. I hypothesized that the age-specific effects of testosterone on corticosterone were related to differential conversion to metabolites (e.g., estradiol), which I tested using androgen receptor (AR) and estrogen receptor (ER) antagonists (flutamide and tamoxifen, respectively) in the presence of testosterone or dihydrotestosterone (DHT). Testosterone produced a similar, albeit non-significant, age-specific pattern of effects on corticosterone as described above, and I found little evidence for effects of receptor antagonists. Androgens reduced post-stress concentrations of progesterone in all age groups, and flutamide prevented the effect. Together, this study provides evidence for developmental shifts in stress responses and their regulation by gonadal hormones. In Chapter 4, I examined the influence of estradiol on HPA function in adult female rats as a first step toward understanding developmental shifts. Ovariectomy (OVX) reduced post-stress concentrations of corticosterone compared with sham OVX and OVX females given estradiol alone or in combination with progesterone. I also found that OVX females had greater cytosolic expression of GR, possibly increasing sensitivity to corticosterone. In a second experiment, I found that progesterone partially mitigated the effect of estradiol on corticosterone release and that gene expression of stress hormone receptors (Nr3c1, Nr3c2), their co-chaperones (Fkbp5, Fkbp4, Bag1), and a co-activator (Src-1) did not change as a function of ovarian hormones. Together, these studies build on previous research investigating developmental and gonadal regulation of HPA activity and provide novel findings regarding potential mechanisms underlying their actions.

Affinity for aloneness (AFA), a tendency to prefer to spend more time alone rather than with others, is assumed to be driven by low social interest rather than by social fears. This is unlike shyness, which is underpinned by a conflict between high social interest and pervasive social apprehension and weariness. Despite the marked motivational differences between these two subtypes of social withdrawal and their potential differential impact on socio-emotional adjustment in childhood and adolescence, AFA is empirically neglected compared to shyness. Shyness was extensively studied and repeatedly linked to a host of negative socio-emotional correlates such as depression, lower social skills, lower self-esteem and peer maltreatment. However, little is known about the socio-emotional impact of AFA on children and adolescents, particularly longitudinally. Despite clear evidence, AFA was suspected as maladaptive due to its affiliation with social withdrawal, a wide umbrella term that has been tied to internalizing problem and peer difficulties. The generalization of findings regarding social withdrawal as a whole to AFA may lead to a pathologization of a normative behavior, increase instances of unnecessary intervention, and inadvertently negatively impact otherwise intact socio-emotional development of children and adolescents. The scarce available knowledge about AFA stems from several persisting gaps in the literature. First, there is insufficient systematic differentiation among subtypes of social withdrawal, and a lack of deliberate simultaneous measurement of specific constructs such as shyness and AFA. Second, there are very few longitudinal studies of both shyness and AFA across childhood and adolescence. Third, there is a lack of contextual investigation of AFA compared to shyness in common life setting in which children tend to spend much of their time, such as organized sports activities. My doctoral dissertation specifically addressed all of the aforementioned gaps in the literature. Results of Study 1, a longitudinal study spanning from Grade 3 to Grade 5, indicated that only shyness, but not AFA, was significantly related to lower social skills and greater peer victimization across time. Study 2 utilized Latent Class Analysis and results indicated that adolescents in Grades 11 and 12 who were high on AFA and low on shyness did not differ from adolescents low on both AFA and shyness (a non-withdrawn group) on measures of socio-emotional adjustment. In Study 3, results of Structural Equation Modeling (SEM) indicated that only shyness, but not AFA, was related to lower positive activity outcomes through lower psychological engagement in the activity. In aggregate, the findings of the present doctoral studies advance the literature on AFA in meaningful ways. Most notably, AFA emerged as a largely benign form of social withdrawal across middle childhood and adolescence. Moreover, Study 2, which appears to be the first person-centered investigation of AFA in adolescence using Latent Class Analysis, provided novel evidence that AFA and shyness are distinct constructs with unique implication for socio-emotional adjustment. These findings carry applied implication for educators and parents seeking to facilitate optimal developmental contexts for children with an AFA.

According to justice motive theory, individuals have a fundamental need to believe that the world is a just place where people get what they deserve, or to have belief in a just world (BJW; Lerner, 1977, 1980). There are several reasons why individuals need BJW that have been proposed in the extant literature (Dalbert, 1999, 2001; Hafer, 2000; Lerner, 1980; Lerner & Miller, 1978; Lipkus, Dalbert, & Siegler, 1996). In the current research, I examine two of these functions: to encourage investment in long-term goals (Callan, Shead, & Olson, 2009; Hafer, 2000; Hafer, Bègue, Choma, & Dempsey, 2005) and to reduce fear of death (Hirschberger, 2006; Pyszczynski, Greenberg, & Solomon, 1997). Moreover, I propose a new function of BJW—to provide individuals with a sense of purpose in life. Specifically, I argue that BJW provides a sense of purpose because, if individuals have BJW, then they can see the world as a place where their lives are both desirable and important. Further, having a sense of purpose in life should in turn improve subjective well-being (Ryff, 1989; Ryff & Keyes, 1995; Ryff, Lee, Essex, & Schmutte, 1994; Zika & Chamberlain, 1992). Therefore, purpose in life, or purpose anxiety, should mediate the association between BJW and well-being. I examined this proposal in four studies. For each study, I predicted that BJW would have an indirect association with positive affect, negative affect, and satisfaction with life, through purpose in life, or purpose anxiety, and that this association would be unique from those through other potential mediators in each model. My hypotheses were supported in each of the four studies. I discuss limitations, topics for future research, and implications for theory as well as reducing victim blame and supporting victims of trauma.

Other-race faces are discriminated and recognized less accurately than own-race faces. The other-race effect (ORE) emerges during infancy and is robust across different participant populations and a variety of methodologies (Meissner & Brigham, 2001). Decades of research has been successful in characterizing the roots of the ORE, however certain aspects regarding the nature of own- and other-race face representations remain unspecified. The present dissertation attempts to find the commonalities and differences in the processing of own- vs. other-race faces so as to develop an integrative understanding of the ORE in face recognition. In Study 1, I demonstrated that the ORE is attributable to an impaired ability to recognize other-race faces despite variability in appearance. In Study 2, I further examined whether this ability is influenced by familiarity. The ORE disappears for familiar faces, suggesting a fundamental difference in the familiar and unfamiliar other-race face recognition. Study 3 was designed to directly test whether the ORE is attributable to a less refined representation of other-race faces in face space. Adults are more sensitive to deviations from normality in own- than other-race faces, and between-rater variability in attractiveness rating of individual faces is higher for other- than own-race faces. In Study 4, I investigated whether the ORE is driven by the different use of shape and texture cues. Despite an overall ORE, the transition from idiosyncratic shape to texture cues was comparable for own- and other-race faces, suggesting that the different utilization of shape and texture cues does not contribute to the ORE. In Study 5, applying a novel continuous-response paradigm, I investigated how the representations of own- and other-race face are stored in visual working memory (VWM). Following ample encoding time, the ORE is attributable to differences in the probability of a face being maintained in VWM. Reducing encoding time caused a loss of precision of VWM for other- but not own-race faces. Collectively, the results of this dissertation help elucidate the nature of representations of own- and other-race faces and clarify the role of perceptual experience in shaping our ability to recognize own- and other-race faces.

Models of affective processing abnormalities in psychopathy have involved both amygdala abnormalities and attentional deficits to peripheral affective information. Neurophysiological bases for the latter are not currently well understood. Often presented as competing explanations for affective traits of psychopathy, these models may instead be compatible, describing different levels of analysis, with the amygdala playing a role in early attention allocation. To explore this possibility, this dissertation was designed to integrate these two areas of the literature by proposing a neurophysiologically-based model of biases in attention to peripheral affective information in psychopathy. This model is centred on the idea that attentional biases seen in psychopathy may result from reduced responsivity of a subcortical thalamus-amygdala circuit that influences the allocation of attention to salient stimuli in the environment during initial stages of processing. Event-related potential (ERP) components that reflect attention allocation during early stages of visual information processing were used to test the hypothesis that individuals high in psychopathic traits would show reduced attention allocation to peripheral information in the form of reduced and/or delayed ERP responses. Explored were the relations between psychopathic personality traits and early ERP responses to simple stimulation of the visual system (Study 1) and to spatially-filtered emotional faces involving implicit versus explicit processing of the stimuli (Study 2). ERP effects related to overall psychopathic trait severity, but also yielded factor-specific ERP response patterns. Study 1 results were consistent with the present hypotheses. Specifically, higher Factor 1 scores (primary, affect-based traits) were associated with reduced attention-related ERP amplitudes in response to a flash stimulus presented peripheral to task performance. Factor 2 severity (secondary antisocial and behavioural traits) was associated with ERP latencies in primary visual cortex. Study 2 also showed somewhat more complex but Factor-specific patterns of early visual processing. Overall, the results were consistent with a reduced responsivity of the thalamo-amygdalar pathway in psychopathy-related individual differences in attention at early stages of visual information processing, both for affective information and simple sensory stimulation. This raises the question of whether such processing differences are a predisposing factor for the development of psychopathic traits.

As do many species, humans visually assess the ability and propensity of others to cause trouble or harm (threat potential), although the mechanisms that guide this ability are unknown. One potential mechanism that may underlie advertisements and assessments of threat is the facial width-to-height ratio (face ratio). The overarching goal of this thesis was to test both the ecological validity of the face ratio (i.e., the extent to which it maps onto an individual’s actual threat potential), and its utility in influencing observers’ first impressions of traits related to threat potential. In Chapter 2, I found that men (n = 146) but not women (n = 76) with larger face ratios were more likely to cheat in a lottery for a cash prize than were men with smaller face ratios. In Chapter 3, to better identify the precise social function of the metric, I examined its differential association with two types of threat-related judgements, untrustworthiness and aggressiveness. The face ratio (n of faces = 141) was more strongly linked to observers’ (n = 129) judgements of aggression than to their judgements of trust, although it is possible that this metric advertises threat potential more generally, of which aggression is a best indicator. In Chapter 4 (which extended some preliminary, additional findings from Chapter 3), I found that observers’ (n = 56) judgements of aggression were strongly correlated with the face ratio (n of faces = 25) even when men were bearded, suggesting that this metric could have been operational in our ancestral past when interactions likely involved bearded men. In Chapter 5, I combined effect sizes from experiments conducted from several independent labs and identified significant (albeit weak) associations between the face ratio and actual threat behaviour, and significant (and stronger) associations between the face ratio and judgements of threat potential. Together, this body of work provides initial evidence that the face ratio, and sensitivity to it, may be part of an evolved system designed for advertising and assessing threat in humans, akin to threat assessment systems identified in other species.