Variation characterizes much of everyday life. People's thoughts, feelings, and behaviors are not static, but change depending on who they are, where they are, and with whom they are. For personality psychologists interested in describing this variation, new and low-cost methods of assessment can describe how people differ from each other on average, as well as how people differ from their own average across multiple real-life situations and social interactions. Researchers use such within-person methods to develop sophisticated models of personality, emotion, and self-esteem that aim to represent real-life variance in experience.

In this dissertation, I extend this within-person approach to the study of emotion regulation and social hierarchy. Researchers consider emotion regulation and social hierarchy to be domains of psychological life that serve important social functions. Yet few studies have examined these domains in real-life social interactions, and no research has examined how these domains change across a person's everyday life.

In Chapter 1, I introduce the topic of within-person variation more formally with a review of key concepts and differences from other approaches to psychology. Specifically, I argue that a within-person approach is fundamental for researchers to understand psychological processes. I then summarize the methods of assessment and analysis that I will use in this dissertation, and develop three broad research questions about within-person processes that guide my empirical research.

In Chapter 2, I present research on within-person variation in expressive suppression – a strategy that people use to regulate their emotions by hiding expressions in the face and body. In contrast to past research that emphasizes the negative consequences of stable suppression use, I find evidence that suppression use can serve adaptive functions when used in specific situations.

In Chapter 3, I focus my within-person approach on the study of social hierarchy. Although past theory differentiates social power (a person's ability to exert influence or control in a situation) from social status (a person's respect or reputation) and from social class (a person's rank in society), these three related dimensions of social hierarchy are not well-differentiated at the empirical level. In this chapter, I demonstrate ways in which accounting for within-person variation supports existing theory and offer new insights that differentiate these related hierarchical dimensions.

Together, the findings reported in these two chapters demonstrate the prevalence and potential of within-person variation in psychological research. In Chapter 4, I summarize the major findings in the two empirical chapters, discuss the broader implications and limitations of this research and within-person methods of assessment more broadly, and conclude with suggested ideas for future research.

There is a plethora of literature linking Extraversion to the experience of positive emotions and Neuroticism to the experience of negative emotions. Further, it has been argued that these relationships have important consequences for well-being. In addition to these main effects of the trait, research on person-situation interactions has shown that individuals have differential reactivity to emotional situations, even identifying some direct causal links using experiments, based on their underlying Extraversion and Neuroticism. However, much less is known about how this differential reactivity might generalize outside of the lab, to naturalistic situations. In Study 1, we test this claim by capitalizing on the natural lockdown that occurred as a result of the COVID-19 pandemic, asking how emotion experience changed due to this lockdown, and whether these changes were moderated by Extraversion, Neuroticism, and the less studied but important trait of Agreeableness. Further, we add an investigation of these potential interactions using facet-level personality. These constructs represent a more specific level of personality analysis than personality traits and have received almost no attention in the literature on the relationships between personality and emotion. However, this increased specificity allows for important clarifying hypotheses about the relationships between personality and emotion to be tested, such as whether the associations between Extraversion and positive emotions are due more to social contact or behavioral activation. In Study 1, we showed that individuals did respond differently to the lockdown based on their underlying Extraversion, Neuroticism and (to a lesser extent) Agreeableness. Further, we showed that the relationship between Extraversion and positive emotions is likely due to behavioral activation more so, or even in place of, social contact. In Study 2, we ask whether these results generalize to a more traditional in lab emotional situation manipulation, using a sad film clip. We capitalize on modern statistical techniques, namely multilevel modelling, to advance the existing work in this area and show that both our results from Study 1, as well as the findings from previous work, which made use of difference scores as dependent variables instead of multilevel models, both generalized well. We discuss the implications of these findings for personality theory, emotion theory, and person by situation interactions, as well as highlight some suggestions for future research.

My dissertation will examine individual differences in interpersonal emotion regulation strategies (Chapter 1), everyday examples of interpersonal emotion regulation strategies (Chapter 2), and experimental evidence for how interpersonal emotion regulation strategies affect recipients (Chapter 3). The beginning of my dissertation was a finding: people reported that more than 90% of the episodes in which they regulated their emotions occurred in social situations (Gross, Richards, & John, 2006). Still, nearly all studies of emotion regulation have focused on intrapersonal (self-directed) processes, and interpersonal emotion regulation processes remain understudied. Interpersonal emotion regulation can take many forms (Zaki & Williams, 2013); in my research, I focus on the efforts one person makes to influence the emotions of another person (other-directed regulation), such as a father who hugs his distressed child to calm her down, a therapist who suggests ways to think more positively about a stressful event to a ruminating patient, a friend who reframes a discriminatory act to counteract its ensuing frustration, and a romantic partner who stonewalls to keep the other from expressing anxiety about their relationship. In other words, I study the specific strategies people may use to influence the emotions of others. I began with the two strategies most studied in the self-directed regulation literature, reappraisal and suppression. I also found an additional process important in the interpersonal domain, namely acceptance (accepting another’s emotions with no attempt to change their emotions). For my dissertation, I use a multi-method approach to examine how these strategies influence social and emotional life.

Who is the person who cares about and values social and cultural diversity? From a basic trait perspective, such a person might be curious—to want to learn about groups outside one’s own—and compassionate—to diversity as an opportunity for collaboration rather than competition. Despite curiosity and compassion’s clear mapping to Openness and Agreeableness within the Big Five, past research indicates that these traits are insufficient to account for the breadth of thoughts, feelings, and behaviors that arise in intergroup settings. In this dissertation we propose a novel personality trait that describes people’s appreciation, embrace of, and preference for social difference in their environment, which we call Openness to Other (O2), in order to better account for individual differences in valuing social diversity and navigating intergroup interactions.In Chapter 1 we described Openness to Other’s nomological network and demonstrate that it is independent of its parent traits, Agreeableness and Openness. We first develop and validate a brief self- report scale to measure Openness to Other, finding that participants can be ordered along it unidimensionally, respond reliably to it, and do not alter their responses to appear more socially desirable. We then demonstrate that O2 relates most strongly to Openness and Agreeableness, in both self- and peer-reports, but that it remains autonomous from each. In addition, we show that O2 was accurately perceived by knowledgeable peers at levels comparable to the other Big Five. We then examine the broad values that motivate people high and low on O2. We found that low-O2 individuals, like those low on Agreeableness or Openness, valued power and tradition. In contrast, those high on O2 valued equality and tolerance, whereas agreeable individuals valued helping and getting along with others and open individuals valued curiosity, creativity, and personal expression. In the domain of intergroup interactions, people high on O2 were described by peers as calm, seeking out such interactions, working to make sure these interactions go well, and seeking opportunities to learn about different cultures. All of these relationships were independent of Agreeableness and Openness. Finally, in the sociopolitical domain, high-O2 people held more positive views toward immigration in general and toward a central outgroup in the U.S. (Muslims) and, importantly, voted against an anti-immigrant presidential candidate (Donald J. Trump). All of these also held independently of Agreeableness and Openness. In Chapter 2 we applied O2 to an important life domain: racial homophily, or having friends and acquaintances who are the same race as oneself. We found that O2 consistently predicted cross-race friendship. Compared to Agreeableness and Openness, O2 had the stronger and only unique effect, suggesting it is the “active ingredient.” High-O2 individuals had an almost equal 1:1 ratio of same-to- different-race network members, whereas low-O2 individuals had 4:1 same-race. These results held for both college students and middle- aged adults, both friends and new acquaintances in the network, and both networks established before and at a diverse university. Finally, when moving to a more diverse environment, high-O2 individuals seemed to take advantage of the new environmental affordances, adding more different-race members to their networks. Overall, these studies advance understanding of person–environment transactions, showing how personality traits matter to the structure of people’s social networks.

How and why do Westerners and East Asians differ in their use of emotion regulation processes? In the present dissertation, I describe five studies that test whether differences in the self-models of Westerners and East Asians lead to culture-specific patterns of emotion regulation. In Study 1, I conduct comparisons between and within cultures to test whether differential exposure to Western and East Asian culture is associated with divergent use of two emotion regulation processes--expressive suppression and cognitive reappraisal. In Study 2, I use an experimental design to prime American versus East Asian cultural identity in bi-cultural East Asian Americans, testing whether there is a causal link between cultural self-models and emotion regulation. In Studies 3 and 4, I present evidence that these cultural differences in emotion regulation are not due to methodological artifacts associated with global self-reports. In particular, I show that similar culture effects emerge when emotion regulation in a specific self-disclosure context is rated by independent judges (Study 3), and when emotion regulation is rated by peers from an individual's real-life social network (Study 4). In Study 5, I test whether Western and East Asian cultural differences in emotion regulation can be explained by two specific cultural mechanisms, namely the interdependent and independent cultural models of self. Findings are consistent across all five studies and show that Westerners use less suppression (but not less reappraisal) than individuals of East Asian cultural origin. In terms of mechanism, these differences seem to be due to the strong emphasis on independence and authentic self-expression in Western cultures, rather than to the strong emphasis on interdependence and interpersonal harmony in East Asian cultures.

This dissertation examined links between Big Five personality measures and work lives in two studies of women in the Mills Longitudinal Study who worked substantially during mid-life (N=91). Study 1 investigated effects of personality on work: how did women who as college seniors scored high on Extraversion (E), Openness (O), and Conscientiousness (C) express these traits in their work lives throughout ascending, maintaining, and descending phases of work involvement from young adulthood to age 70? Personality did not predict either work or education variables in the early years after college (the early 1960s) when the culture was traditionally gender-typed and family-oriented. However, as women's roles changed, E, O, and C became generally and substantially related to work variables as expected from personality theory and research. Nonetheless, specific cultural influences (e.g., such as the link between C and the traditional women's role) affected the timing of involvement in work, and some of the women made personality-syntonic choices (e.g., in terms of nature of work and partners) that affected their financial security at age 70.

The second study investigated effects of work on personality: how can early work experiences be conducive to subsequent personality change? This study related work satisfaction and status level of work to decreasing levels of Neuroticism over a period of middle age in which many Mills women were highly engaged in work. Consistent with past research, higher work satisfaction at age 43 predicted decreases in Neuroticism from 43 to 61--that is, the women showed a significant improvement in a broad domain of psychological functioning. As predicted, this positive and lasting effect of work satisfaction was mediated by the positive impact that their work experience had on the women's self-confidence. In contrast, occupational attainment per se was not associated with decrease in Neuroticism.

Together, the two studies illustrate the mutually interactive relation between personality and work: early personality traits can importantly shape subsequent work lives (Study 1) but, in turn,early work experiences can shape subsequent personality development (Study 2).