The positive appraisal style theory of resilience (PASTOR) outlined by Kalisch et al. represents an innovative development in the study of resilience, capturing another step in the paradigm shift from investigating disease to health (Jayawickreme et al. Reference Jayawickreme, Forgeard and Seligman2012). The goal of this commentary is to highlight how PASTOR can both help clarify critical questions in and benefit from engaging with new research in personality science in developing a coherent theory of resilience.

Recent advances in personality psychology have provided new perspectives on behavioral flexibility – and consistency – across situations (Fleeson & Jayawickreme Reference Fleeson and Jayawickreme2015). Such flexibility can serve as a tool for promoting resilience as defined by PASTOR. Despite the widespread belief that personality is stable, a large literature has revealed that on average, most people display moderate, mostly positive, amounts of trait change across the lifespan (Roberts et al. Reference Roberts, Walton and Viechtbauer2006). Hence, individuals may be able to influence the degree to which their personality varies and changes (Edmonds et al. Reference Edmonds, Jackson, Fayard and Roberts2008). In addition, studies using experience sampling methods have demonstrated a surprisingly high level of variability in trait-relevant behavior in everyday life, with most individuals acting in ways that span the entire continuum of each trait dimension (Fleeson Reference Fleeson2001). Furthermore, individuals have the ability to convincingly change their trait-relevant behavior (or personality “state”) in the moment, when instructed to do so (Fleeson et al. Reference Fleeson, Malanos and Achille2002; McNiel & Fleeson Reference McNiel and Fleeson2006). Of note, people can change their levels of happiness by “enacting” personality states associated with happiness, such as extraversion (Fleeson et al. Reference Fleeson, Malanos and Achille2002; McNiel et al. Reference McNiel, Lowman and Fleeson2010; Zelenski et al. Reference Zelenski, Santoro and Whelan2012). It should be noted, as well, that personality states have the same content as a trait but for shorter duration, and that states and traits are isomorphic in some regards. Part of having a trait is simply acting that way somewhat more often, and acting a certain way is similar to being that way (Jayawickreme et al. Reference Jayawickreme, Meindl, Helzer, Furr and Fleeson2014).

Hence, personality traits are stable in the sense that there is reliable between-person variation in aggregate over time, and flexible in the sense that there is also substantial within-person variation in an individual's trait-relevant behavior (or personality states) depending on situational and internal cues (Fleeson Reference Fleeson2001; Reference Fleeson2004). We need more research on which specific personality traits (or “resilience-conducive” traits, as Kalisch et al. term them) might promote a flexible and positive reappraisal style as posited by PASTOR. Moreover, it's an exciting idea for new research: harnessing behavioral variability (Blackie et al. Reference Blackie, Roepke, Forgeard, Jayawickreme, Fleeson and Parks2014; Fleeson & Jayawickreme Reference Fleeson and Jayawickreme2015) to develop flexible, PASTOR-based interventions, resulting in lasting changes in the cognitive machinery that boosts resilience (see also Blackie et al. 2015).

Relatedly, PASTOR has implications for helping researchers understand empirical overlap between resilience and closely related constructs. To illustrate this point, we propose that PASTOR may help clarify the relationship between resilience and posttraumatic growth – positive psychological change experienced as a result of the struggle with highly challenging life circumstances (Jayawickreme & Blackie Reference Jayawickreme and Blackie2014). Whereas resilience generally is defined as the absence of negative outcomes during or following potentially harmful circumstances (e.g., Seery et al. Reference Seery, Holman and Silver2010), posttraumatic growth corresponds to increases in positive outcomes after adversity. (We note that Kalisch et al.'s definition of resilience conflates these two distinctions, as they define resilience as “any trajectory that eventually leads to levels of functioning that are comparable to or even better than at the outset”; sect. 2, para. 3; emphasis added.) Posttraumatic growth is purported to occur in five distinct life domains – individuals report experiencing a greater appreciation of life, more-intimate social relationships, heightened feelings of personal strength, greater engagement with spiritual questions, and the recognition of new possibilities for their lives (Tedeschi & Calhoun Reference Tedeschi and Calhoun2004). Posttraumatic growth is generally viewed as both a set of processes (e.g., coming to terms with adversity; identifying and experiencing cognitive, behavioral, and affective changes) and a set of outcomes (e.g., great satisfaction with life, wisdom).

In spite of the theoretical differences between resilience and posttraumatic growth, empirical evidence has shown that people high in traits such as cognitive complexity, self-efficacy, and dispositional hope are more likely to report growth (Tedeschi & Calhoun Reference Tedeschi and Calhoun1995; Tennen & Affleck Reference Tennen, Affleck, Tedeschi, Park and Calhoun1998). In other words, people who report growth may in fact be those who were more resilient to begin with. As a result, much debate remains concerning the exact nature of posttraumatic growth – an issue that the PASTOR framework may help clarify. To date, most of the scholarship in this area has focused on documenting self-reported retrospective changes (i.e., perceptions of past changes). Ongoing and future research in this area is seeking to determine whether or not retrospective self-perceptions of change also correspond to changes in behavior and cognition measured longitudinally (Jayawickreme & Blackie Reference Jayawickreme and Blackie2014; Roepke et al. Reference Roepke, Forgeard and Elstein2014; Schueller et al. Reference Schueller, Jayawickreme, Blackie, Forgeard and Roepke2015). This research can tease out the degree to which resilience precedes growth, and the extent to which both resilience and growth are brought about by or associated with the flexible and positive reappraisal style as proposed by PASTOR. Hence, PASTOR has critical implications for meaningfully distinguishing between the two constructs and pushing further the study of psychological functioning under conditions of adversity.

In addition, and related to this, PASTOR can help researchers design thoughtful experiments and/or interventions aimed at promoting growth following adversity. More specifically, future research may examine the usefulness of fostering selected personality states (as described above). For example, a review of past research suggested that openness to experience, extraversion, and agreeableness (candidate “resilience-conducive” traits) predict adaptive outcomes following adversity (Linley & Joseph Reference Linley and Joseph2004). Future research could assess whether experimental interventions promoting open, extraverted, and/or agreeable behaviors may lead to positive and flexible cognitive styles described by PASTOR, and in turn, to resilience or growth.