What predicts sociable behavior? While main effects of personality and situation characteristics on sociability are well established, there is little evidence for the existence of person-situation interaction effects within real-life social interactions. Moreover, previous research has focused on self-reported behavior ratings, and less is known about the partner’s social perspective, i.e. how partners perceive and influence an actor’s behavior. In the current research, we investigated predictors of sociable behavior in real-life social interactions across social perspectives, including person and situation main effects as well as person-situation interaction effects. In two experience-sampling studies (Study 1: N = 394, US, time-based; Study 2: N = 124, Germany, event-based), we assessed personality traits with self- and informant-reports, self-reported sociable behavior during real-life social interactions, and corresponding information on the situation (categorical situation classifications and dimensional ratings of situation characteristics). In Study 2, we additionally assessed interaction partner-reported actor behavior. Multilevel analyses provided evidence for main effects of personality and situation features, as well as small but consistent evidence for person-situation interaction effects. First, extraverts acted more sociable in general. Second, individuals behaved more sociable in low-effort/positive/low-duty situations (vs. high-effort/negative/high-duty situations). Third, the latter was particularly true for extraverts. Further specific interaction effects were found for the partner’s social perspective. These results are discussed regarding their accordance with different behavioral models (e.g., Trait Activation Theory) and their transferability to other behavioral domains.

What does it mean to know a person? In his famous article, McAdams (1995) addresses this question from the perspective of personality psychology and concludes that personality traits are “the psychology of the stranger.” To really know someone, you need to know more than just how they typically think, feel, and behave on average (a common definition of traits). You need to know how their thoughts, feelings, and behaviors change depending on their role and context, why those fluctuations occur (the underlying motives and causes of those patterns), and how they make sense of their own patterns over time (their life narrative). In this essay, we argue that although there has been little empirical work on within-person fluctuations in personality, the time is ripe to examine these patterns. New technology has made it possible to quantify momentary thoughts, feelings, and behaviors, and to track the contextual factors that underlie these fluctuations (i.e., “personality signatures”). By capturing individual differences at this dynamic level, we can gain a better understanding of how people differ from one another. This will also open the door to new research questions, such as investigating the amount of insight people have into their own and others' personality signatures.

People fluctuate in their behavior as they go about their daily lives, but little is known about the processes underlying these fluctuations. In two ecological momentary assessment studies (Ns = 124, 415), we examined the extent to which negative and positive affect accounted for the within-person variance in Big Five states. Participants were prompted six times a day over six days (Study 1) or four times a day over two weeks (Study 2) to report their recent thoughts, feelings, and behaviors. Multilevel modeling results indicated that negative and positive affect account for most, but not all, of the within-person variance in personality states. Importantly, situation variables predicted variance in some personality states even after accounting for fluctuations in affect, indicating that fluctuations in personality states may be more than fluctuations in state affect.

Who are the people who maintain satisfying friendships? And, what are the behaviours that might explain why those people achieve high friendship satisfaction? We examined the associations between personality (self–reports and peer–reports) and friendship satisfaction (self–reports) among 434 students. We also examined whether role personality (how people act with their friends) and quantity and quality of social interactions using ecological momentary assessment mediate the associations between personality and friendship satisfaction. Extraversion, agreeableness, conscientiousness and (low) neuroticism were associated with higher levels of friendship satisfaction. These associations could not be accounted for by individual differences in role personality. In addition, our results suggest that quantity of time spent with friends and quality of friend interactions (depth of conversation, self–disclosure and lack of emotion suppression), although associated with friendship satisfaction, do not account for the associations between trait personality and friendship satisfaction. Future research should examine other potential interpersonal processes that explain why some people are more satisfied with their friendships than others and the consequences of friendship satisfaction (e.g. for well–being). Copyright © 2015 European Association of Personality Psychology

Dunlop makes an admirable attempt to incorporate contextualized personality within McAdam's three-level model of personality. However, it relies on two assumptions we believe to be unwarranted. Firstly, we contend that viewing contextual personality as exclusively a 'self' phenomenon is unnecessary. Secondly, examination of specific personality processes within each level is possible without assessing all levels simultaneously. Moreover, theory needs to be articulated about the connections among levels. Work on contextual personality should build upon the strong foundation of the trait approach. Copyright (C) 2015 European Association of Personality Psychology

With over 800 million active users, Facebook is changing the way hundreds of millions of people relate to one another and share information. A rapidly growing body of research has accompanied the meteoric rise of Facebook as social scientists assess the impact of Facebook on social life. In addition, researchers have recognized the utility of Facebook as a novel tool to observe behavior in a naturalistic setting, test hypotheses, and recruit participants. However, research on Facebook emanates from a wide variety of disciplines, with results being published in a broad range of journals and conference proceedings, making it difficult to keep track of various findings. And because Facebook is a relatively recent phenomenon, uncertainty still exists about the most effective ways to do Facebook research. To address these issues, the authors conducted a comprehensive literature search, identifying 412 relevant articles, which were sorted into 5 categories: descriptive analysis of users, motivations for using Facebook, identity presentation, the role of Facebook in social interactions, and privacy and information disclosure. The literature review serves as the foundation from which to assess current findings and offer recommendations to the field for future research on Facebook and online social networks more broadly.