Building a Dynamic Adaptational Process Theory of Resilience (ADAPTOR): Stress exposure, reserve capacity, adaptation and consequence

Abstract

A Dynamic Adaptational Process Theory of Resilience (ADAPTOR) incorporates a synchronistic interplay of reserve capacity, adaptation, and consequences in the context of the larger exposome. This conceptualization of resilience centers on the argument that individuals can ‘build’ resilience by drawing upon their various reserve capacities to effectively adapt to challenging contextual factors, and that this process has long-term consequences for health and wellness trajectories. These theoretical arguments were tested using the Notre Dame Study of Health & Well-being—COVID Study (NDHWB-CS), which is a multi-timescale, longitudinal study of data collected from September of 2020 through February of 2022. We included 444 participants (Age Range = 26–90, M = 62.23, SD = 14.26), and used hierarchical linear modeling to assess the effects of global perceptions of stress reactivity (reserve capacity), daily affective reactivity (adaptation), as well as negative pandemic exposure (exposome) on trajectories of depression and anxiety (consequences) across the COVID-19 pandemic. Most pertinent to ADAPTOR, an interactive effect indicated that reserve capacity and adaptation may serve compensatory roles for one another in the context of a more stressful exposome, whereas the synchrony between reserve capacity and adaptation may be important in the context of a less stressful exposome. These findings support the ADAPTOR framework, such that reserve capacity, adaptation, the exposome and their confluence differentially impact various consequences. This ultimately highlights the importance of taking a dynamic, process-oriented, multi-faceted approach to studying resilience.

Adaptor, n. one who is capable of adapting well to differing situations.

― www.yourdictionary.com/adaptor

Over a lifetime, most people are exposed to major life events, with many experiencing turbulent lives due to the “pile up” of day-to-day stressors. Not everyone, however succumbs to the mental and physical health consequences of this adversity. An explanation for these differences is that some individuals are more “resilient” than others, and show sustainability and even growth in the face of trauma, chronic strains, or other life events. One major limitation to understanding the role of resilience in the face of hardship, however, is that researchers operationalize resilience in different ways. That is, some refer to resilience as a trait that people have to differing degrees, and that may be composed of a multiplicity of attributes. From this perspective, resilience is defined as the ability to see difficulties as challenges to be mastered rather than threats to be endured (Kobasa & Puccetti, 1983), and often includes individual attributes like optimism, personal competence, and self-efficacy, or even external resources like family cohesion and social support (e.g., Windle et al., 2011). Other researchers conceptualize resilience as a process, focusing on adaptation, which can be indexed as the extent to which stress affects functioning, or strategies used to actively cope with the adversity. Sample definitions include the process by which people harness the resources to sustain well-being (Panter-Brick & Leckman, 2013), as well as the capacity of a dynamic system to adapt successfully to disturbances that threaten the viability, function, or development of that system (Masten, 2019). Still, others assess resilience as a set of consequences, and measure this by either following individuals who did better than expected given their circumstances, or by identifying trajectories of decline, recovery, sustainability, or growth following an adverse event. These definitions incorporate attributes like the ability to bounce back from adversity (Block & Kremen, 1996) or to withstand the impact of major or traumatic stress, meaning resilient individuals remain functional or unharmed on some deep, lasting level (Hobfoll et al., 2015; Luther et al., 2000; Ong et al., 2009; Zautra, et al., 2008). Finally, our understanding of resilience is embedded in the exposome, which describes internal and external environmental exposures (including chemical, physical, biological, and social factors) that an individual encounters throughout life (Miller, 2020).

Although all these conceptualizations contribute insight into resilience, in isolation, these individual perspectives are incomplete. The allegory of the blind men trying to understand an elephant comes to mind. In this parable by American poet John Godfrey Saxe (1872), six blind men meet an elephant for the first time. Each man touches a different part of the elephant and makes predictions about what the elephant is like. The result is disagreement, because their perceptions of the elephant are different from each other due to their limited exposure. An elephant is simultaneously like a “fan (ear),” “spear (tusk),” “tree (leg),” “snake (trunk),” “rope (tail)” and “wall (side).” It is also many other adjectives, because it is an intricate, magnificent animal! One moral to this folktale is “we have to remember that what we observe is not nature in itself, but nature exposed to our method of questioning” (Heisenberg, 1958, p. 58). Here, if the blind men put their perspectives together, they could easily garner a more complete picture.

In the case of resilience, few studies have integrated adaptation, reserve capacity and consequence to conceptualize resilience as a complex process that is embedded in a larger context (exposome), changes over time, and is unique for all individuals. Therefore, we introduce A Dynamic Adaptational Process Theory of Resilience (ADAPTOR), which incorporates a synchronistic interplay of reserve capacity, adaptation, and consequences embedded in a broader exposome (see Figure 1a; described in more detail below). The purpose of this article is to 1) define aspects of the resilience process, including reserve capacity, adaptation, and consequences; 2) integrate these components into a unified theory of resilience, including context, change and individual differences; 3) describe data collection and analytic strategies that can distinguish between-person differences from within-person change, test the multidimensional nature of the stressor, response and outcome, and create a deeper understanding of the short- and long-term impacts of adversity; and 4) promote more rigorous approaches to the overall research enterprise. To explicate the resilience process, we will use data from the Notre Dame Study of Health & Well-being—Covid Study (NDHWB-CS).

Figure 1. Illustration of A Dynamic Adaptational Process Theory of Resilience (ADAPTOR).

Note. 1a) The component parts include the reciprocal and synergistic influences of reserve capacities, adaptation and consequence. This process is embedded in the exposome and changes over time. 1b) Depiction of the interrelated psychological, social and physical assets that comprise reserve capacity. 1c) Typical profiles of consequences to stress portrayed in resilience research.

ADAPTOR: Reserve Capacity, Adaptation, and Consequence

Reserve Capacity

Resilience is often defined in the extant literature as a trait or set of characteristics that individuals possess to differing degrees. These qualities are used to help individuals deal with adverse situations, which can range from daily hassles to traumatic life circumstances or chronic deprivation. These attributes can be conceptualized directly, such as dispositional or ego resilience, hardiness, and grit, or more indirectly, via supportive relationships, coping strategies or physical, cognitive or financial reserves. The Resilience Portfolio Model is a strengths-based framework that was created to provide a description of the protective factors and processes that promote resilience in individuals exposed to violence (Grych et al., 2015).

In our context, however, we suggest the term reserve capacity to depict this type of resilience, which is in essence, ‘on reserve,’ and can be drawn upon when needed to face adversity. As illustrated in Figure 1b, reserve capacity refers to the individual’s physical, social and psychological capabilities for responding effectively to challenging conditions. Although the figure is not exhaustive of potential reserve resources, it depicts many of the dimensions studied in previous research (e.g., Masten, 2014). Some of these attributes may be influenced by genetic propensities, occur due to early life experiences, or represent structures in one’s broader social, political and economic contexts that individuals have less direct control over. As such, these capacities may show stability across the lifespan, whereas other reserve capacity characteristics, such as availability of social support or health-related behaviors, may be much more malleable. Regardless, it is the density and diversity of these assets (Grych, et al., 2015), in addition to the flexibility and focus of their use, that is more important than any given characteristic. In other words, from the ADAPTOR perspective, it is not only “what” you have, but “how” and “when” you use it.

Defined in this way, reserve capacity can be developed, and represents flexibility across time scales, contexts of the larger exposome, and attributes of interest. A construct related to reserve capacity is plasticity (Hobfoll, et al., 2015). Unlike trait resilience, plasticity represents individual differences in the ability to change in the face of adversity, for good or for ill. In other words, one’s response to stress (e.g., through training, intervention and practice or lack thereof) can enhance or weaken reserve capacities. Another way in which reserve capacity can be developed is through the concept of steeling (i.e., preparing oneself to do or face something difficult). From this perspective, steeling (sometimes called inoculation) is the tendency for experiencing stress to enhance coping capacity, which aids in the response to future stressors (Rutter, 2012). It should be noted that, like the concept of plasticity, exposure to stressors can decrease reserve capacity through sensitization or kindling effects (see Monroe & Harkness 2005), or increase reserve capacity through steeling effects (Rutter, 2012) or challenge (see Garmezy et al., 1984). Thus, rather than a trait, reserve capacity represents the simultaneous, and synchronized, unfolding of increases, decreases and maintenance in adaptive potential.

Adaptation

A second piece to understanding the resilience puzzle is to capture how and in what ways individuals actually navigate, accommodate or adjust to their stressful experiences in real time. That is, what are the means by which people use their reserve capacities to produce outcomes? We refer to this as adaptation, or the process of changing to suit different conditions. Here, the goal is to understand the flexibility and responsiveness of stress regulation systems to daily hassles, chronic strains, and adverse life events. One description of this coping process, referred to as a flexibility sequence, proposes that when encountered with a stressor, people must gain an understanding of the situation, choose the best response available to them, and monitor how the response is working (Bonanno, 2021). This sequence highlights the process that occurs between exposure and outcome.

Elder (1996), in his Life Course Theory, describes the Control Cycle, which is the foundation for individual change (either growth or decline). In brief, when an individual loses his/her sense of control (e.g., due to stress, loss, change), there is a disparity between demands and resources and/or goals and accomplishments. As this balance changes, the control potential is threatened and adaptive resources are called into play to regain that sense of influence over one’s life. According to the Accentuation Principle, adaptive responses are shaped by these changing situations and the response depends on the social and psychological resources that individuals bring to bear on the shifting context (Elder, 1996). Thus, within constraints, people plan and choose among options that become the building blocks of their evolving life course. Individuals’ choices are influenced by the specific situation and their interpretation of it, as well as their dispositions and life experiences. In this way, control strategies shape individuals’ adaptation to threats from the exposome, and provide an important component of the development of the resilience process. The related theory of Selective Optimization with Compensation (SOC), is a strategy for improving health and well-being in older adults (Baltes, 1987). From this lens, it is recommended that individuals select and optimize their best abilities while compensating for declines and losses. Although this was designed to explain more optimal aging, the concepts of SOC relate to identifying, matching, and using active coping strategies to deal with adversity.

How might this work? Self-regulation, be it physiological, cognitive, emotional or behavioral, is a key component to this process. Agency is the capacity to control and regulate attributes such as attention, arousal, or emotion to produce a particular objective (Haggard & Tsakiris, 2009). Cognitive abilities, such as executive function (e.g., working memory, selective attention, inhibition, delayed gratification and self-control), are the mental processes that enable us to plan, focus attention, remember information and manage multiple tasks successfully (Diamond, 2013). Other regulation skills, such as reframing or reappraisal (Gross, 2019; 2015), meaning making through culture or religion (Unger, 2013), garnering support and empathy from others (Southwick, et al., 2016), or mobilizing positive emotions to produce differential engagement, responsiveness, and positive mood savoring (Ong et al.,2010) or even to “undo” the detrimental effects of stress on negative emotions (Fredrickson, 2000), are each importantly involved in stress reactivity, regulation and recovery. All represent adaptational processes or mechanisms by which reserve capacities are used to adjust to adversity and to produce more positive outcomes.

At a more micro level, Bergeman et al. (2020) argue that the interplay among dynamic systems involved in human functioning, such as emotion, cortisol or blood pressure, are influenced by stressful experiences, resulting in system-level dysregulation (e.g., negative mood, elevated cortisol or blood pressure). Although dysregulation in and of itself is not harmful to functioning, repeated hits or prolonged disruption can result in detrimental physical and mental health effects, known as allostatic load (Lupien et al., 2006, McEwen, 1988). Researchers using a dynamic systems perspective suggest that humans are self-regulating organisms, and when the system of interest is perturbed, that system has a propensity to return to a stable state, referred to as equilibrium (Boker, 2001, 2002; Boker & Bisconti, 2006). Thus, when stress perturbs the system, the process of adaptation utilizes attributes in our reserve capacity to cope with the adverse circumstance to stabilize the system(s) of interest. Here, important indicators of adaptation reflect the degree of stress reactivity (or coupling, which indicates the dynamic effect of stress on response; Montpetit et al., 2010) and the timing and level of stress recovery (e.g., returning to equilibrium; Bergeman et al., 2020).

Consequence

A third way to conceptualize resilience is as an outcome (see Figure 1c), which incorporates descriptions such as “better than expected,” “bounce back from adversity,” or “grow in the face of challenge.” Researchers using the “better than expected” framework (see Garmezy et al.,1984; Rutter, 1988; Werner & Smith, 1992) focus on groups of individuals thought to be at risk for developing psychiatric problems due to genetic propensities, family history (e.g., abuse), current symptoms (e.g., antisocial behaviors; isolation), or disadvantaged environments (e.g., poverty). Much of the early work in the resilience space centered on outcomes of children exposed to these disadvantaged situations. Other research from this perspective focuses on physical resilience and considers the effects of health history, concomitant conditions, or lifestyle factors (termed physical reserve) on post-surgical or disease outcomes (Whitson, et al., 2018). Of interest here is the actualization of one’s potential and the expected recovery differential (i.e., the actual recovery profile compared to the expected trajectory; Whitson et al., 2021). Thus, rather than focusing on a specific event, there is an emphasis on people who are at elevated risk for negative life consequences, yet successfully avoid these detrimental outcomes. The knowledge gained is the understanding of why some individuals show unexpected positive outcomes to the ‘slings and arrows’ of life.

More recent research has defined alternative outcomes (Infurna & Luthar, 2018), including recovery (i.e., a bounce back from the detrimental effects of the exposure), sustainability (i.e., maintaining functioning in the face of a stressful event), decline (i.e., giving up, getting sick or losing hope;), or growth (i.e., seeing the adversity as a challenge and growing and improving as a result of the experience). These patterns also include post-traumatic growth (i.e., growth seen in individuals who experience a life crisis or an especially traumatic event; Jayawickreme & Blackie, 2014). Researchers use different terminology and combinations of these consequences of the stress-response dynamic. Bonanno (2004), for example, proposes that there are four prototypical patterns of disruption to normal functioning following trauma or loss, including: chronic disruption (i.e., no return to previous levels of functioning), delayed grief (i.e., reaction to the event is not immediate), recovery (i.e., eventually regaining previously levels of functioning) and resilience (i.e., maintaining a stable equilibrium throughout the stress exposure and aftermath). He suggests that the resilience pattern is quite common. Other researchers (e.g., Infurna & Luthar, 2018) disagree, and have shown that in cases in which multiple outcomes are considered, the ability to sustain functioning is much rarer. For example, in an assessment of resilience in the face of spousal loss (Infurna & Luther, 2017), the proportion of individuals who were deemed “resilient” based on the study’s definition differed across outcomes: life satisfaction (66%), negative affect (26%), positive affect (19%), general health (37%) and physical functioning (28%). Across all outcomes only 8% were considered resilient. Thus, one domain may be sustained in the face of adversity, but that does not mean that all are.

One problem with focusing on just the consequences is that resilience has to be inferred from these differences in outcome among individuals who may have experienced different levels and types of adversity (Rutter 1987). In the end, whether resilience is common or rare should not be our focus; the important issue is the type of stressors to which people are exposed and the process by which they adapt to, and resolve, them (Infurna & Luthar, 2018). Research that incorporates the dynamic interactions of reserve capacities and adaptational strategies to predict outcomes will help us to better understand the complexities of the consequences of stress exposure within individuals over time.

Exposome

As indicated in Figure 1a, the resilience process is embedded in the exposome. The exposome represents all environmental (i.e., non-genetic) exposures from conception until death (Miller & Jones, 2014). In other words, it is a measure of accumulated environmental influences and the associated biological responses throughout life (for a review, see Niedzwiecki et al., 2019). Although understanding the exposome in its entirety is beyond the scope of this discussion, a focus on the type or source of stress (and the multiplicity or diversity of different events), its intensity and duration, stressor “pile up” or turbulence, and the ability to anticipate the adversity are important to consider (see Epel, et. al., 2018; Ong & Leger 2022). At the extreme, these environmental exposures can include toxic situations of abuse and neglect, a history of discrimination or marginalization, experiences of traumatic events and extreme economic disadvantage.

One attempt to organize the complexities of the exposome is represented by the Ecological Theory of Human Development, which describes the mutual accommodation between the growing organism and the environments in which they live (Bronfenbrenner, 1977). Here, the ecological environment is a nested arrangement of structures. The Microsystem represents the person’s proximate surroundings (e.g., home, school, work), which encapsulates how the individual engages in certain activities while occupying a specific role (e.g., friend, grandparent or employee). The Mesosystem describes the interrelations among the major microsystems that include the developing person at a particular time in his/her life. The Exosystem is an extension of the Mesosystem, integrating other social structures that do not themselves include the developing person, but influence the settings in which the person does belong. The Macrosystem encompasses the institutional patterns of the culture/subculture (e.g., economic, social, and political systems), and the Chronosystem is the dynamic effects of historical changes over time. Although this perspective does not explicitly identify the context that any given individual experiences at any given point in time, it provides a relational structure of environmental exposures from immediate to distal.

In addition to the detrimental environmental exposures, the ADAPTOR conceptualization of resilience will be also affected by the positive history of dynamic interactions between the person and their context, including family, peers, school, work, community, and the natural and built environment. Here, attributes such as family and friend support are important. The concept of cultural resilience, for example, goes beyond a person’s own individual assets to include the support of larger sociocultural factors to aid in adjusting to and overcoming adversity (Clauss-Ehlers, 2015). In fact, it has been suggested that “relationships lie at the roots of resilience” (Luthar & Brown, 2007, p. 947). Thus, the interface with the exposome includes not only stress factors, but incorporates reserve resources as well.

Putting it all together: ADAPTOR

Whether the focus of a program of research is on reserve capacity, adaptation, consequence, or their confluence, the risk-resilience process will depend on the co-action of multiple systems as they come together in the functioning of the individual. As is depicted in Figure 2, the resilience process builds upon itself. On the positive side, effectively dealing with adverse circumstances can produce additional reserve capacity through toughening, inoculation, or steeling. Indeed, developmental theories of competence evoke what are referred to as positive cascades, which suggest that effectiveness in one domain of competence during one period of life becomes the framework on which later competencies in the same, or even newly emerging, domains can develop (see Masten et al., 2006). Accordingly, exposures to stress that promote effective coping can result in increased reserve capacity that affords better scaffolding for dealing with future stressors and will ultimately produce more optimal outcomes. This, in turn, sustains the positive synergistic cascade. Hence, ADAPTOR suggests a resilience system that builds resources and enhances adaptive outcomes, which contribute to new reserve capacities.

Figure 2. ADAPTOR Reflects a Process that is Malleable and Changes over Time and Context.

Note. Although many options are possible (i.e., it is not necessarily linear), here we illustrate positive and negative cascades. The interlocking ovals over time depict the ways in which the adaptational process and stress consequences can, in turn, produce vulnerabilities or potential (positive growth) in reserve capacities.

On the detrimental side, however, ineffective adaptation to challenges can diminish reserve capacity by increased sensitization, emotion dysregulation, or negative health cascades. To be clear, the purpose here is not to blame the victim of intense stressors or horrific events, but to understand that regardless of the source of the lack of adaptation (e.g., extreme exposome, depleted reserve capacity), individuals who show greater dysregulation manifest changes in sympathetic nervous system response (primary reaction), including inflammatory markers, emotion, or immune functioning, which can produce negative outcomes (secondary effects), including increased lipid levels, decreased glucose tolerance, depressed or anxious states, and higher blood pressure (McEwen, 1988), and ultimately results in disorders (tertiary outcomes) like cardiovascular disease, diabetes, cognitive decline, or depression (Bergeman, et al., 2020).

Exposure to stress can also modify DNA methylation, which in turn alters gene expression in ways that can contribute to disease phenotypes, such as cardiovascular disease or cognitive impairment (Vidrascu, et al., 2019) and has been used to distinguish between resilient and non-resilient individuals (Lu, et al., 2021). More specifically, early life stress (e.g., abuse) can have long term consequences, again via methylation, that persist into adulthood and produce detrimental outcomes (Cicchetti & Handley, 2017; Palma-Gudiel, et.al., 2015). Other examples that show the reach of early disadvantage include the Swiss indentured child labor survivors (Thoma, et al., 2021), Whitehall studies (Marmot et al., 1991), and the long-term impact of discrimination (Pascoe & Smart Richman, 2009).

Another way in which these negative patterns of dysregulation have been explained is through habitual processes (Epel, et al., 2018). Habitual Processes are defined as 1) mental filters (i.e., cognitive biases that influence the interpretation of stressors) or 2) allostatic states (i.e., the basal levels of functioning of our regulatory systems; similar to allostatic load described earlier). From this perspective, individuals may have a history of exposure to adversity that, through the mental filter, may amplify one’s cognitive and emotional responses and result in an exaggerated threat appraisal. Physiologically, allostatic states can reflect prolonged dysregulation or blunted stress reactivity (e.g., cortisol response). Thus, the goal is to establish not only how the system adapts to disruption, but also the antecedents and consequences of that process.

Ong and Leger (2022) describe four dynamic outcomes that demonstrate resilient responses: dampened reactivity (i.e., fewer changes in affect, cognition or physiology in response to stress), accelerated recovery (i.e., quicker return of affective, cognitive and physiological systems to equilibrium), toughening/inoculation (i.e., exposures to stressors that promote effective coping; steeling) and richness and balance (i.e., spread of stressors across multiple domains, such that the stressors are appraised as manageable, rather than a single overwhelming event). Because these micro approaches are by their very nature more dynamic, they better integrate ADAPTOR conceptualization of resilience. For example, the first two outcome definitions fit well with the micro indicators of regulation, the third relates to the development and malleability of reserve capacity, and the final definition relates to the exposome (and how one interprets and relates to it, which is itself an adaptive capacity).

To understand resilience using ADAPTOR, we recommend three methodological components: 1) capture the dynamic nature of reserve capacity, adaptation and consequence, 2) understand the context in which it transpires, and 3) identify the time scale at which it can be observed (Bergeman et al., 2020). This conceptualization of resilience as a process that is embedded in a larger context, changes over time, and is different for everyone necessitates research designs that include data at multiple time scales (e.g., in the moment, over short bursts of time, or across months, years or decades), with both nomothetic (between-person) and idiographic (within-person) information. These intensive, longitudinal collection strategies enhance our ability to see “real time” moments of change and allow for the understanding of the precursors, concomitant influences, and sequelae across larger segments of the lifespan, which improves the ecological validity of the findings, strengthens the ability to make causal inference, and minimizes recall error (Ong & Leger, 2022). The use of assessments across multiple timescales can inform how a system (e.g., emotion, blood pressure) at the immediate level is perturbed in the context of stress or over time to produce dysregulation and disease at a more macro-level or alternatively, to identify the reserve capacities that buffer or adapt to stress and lead others to thrive (Bergeman, et al., 2021).

Notre Dame Study of Health & Well-being—COVID Study (NDHWB-CS)

Adverse events, such as a world-wide pandemic, can and often do occur alongside other ongoing chronic or acute events. Accordingly, although everyone experienced the pandemic, there were important individual differences in its effects on day-to-day life. We cannot begin to test the totality of the effects of the COVID-19 pandemic and the ADAPTOR conceptualization of resilience, but we can discuss pieces of the resilience process and test it in the context of this major life stressor that was universally experienced. Thus, to explicate the ADAPTOR conceptualization of resilience, we used data from the Notre Dame Study of Health & Well-being-Covid Survey (NDHWB-CS; see Nelson & Bergeman, 2021, for recruitment details), which includes a subset of 473 participants from the parent NDHWB (Bergeman et al., 2021) who completed 5 waves of daily diary data (28 days/wave) every 6 months during the first 2 years of the pandemic (starting in April 2020 and last collected February 2022), as well as questionnaire data collected in Waves 2–4 (September 2020 through February 2022).

The present analyses included 444 subjects who participated in Waves 2–4 of the NDHWB-CS (see Supplementary Material for full method and results sections). The present sample spanned adulthood in age (Range = 26–90, M = 62.23, SD = 14.26), and most participants were White (84.70%), female (66.44%), married (50.68%), and educated through high school (98.63%), with an annual household income of $40,000 or more (61.09%). Adaptation was indexed through affective reactivity, which was operationalized as individuals’ daily, linear relation between perceived stress and negative affect. Thus, we assessed the evolving ability of individuals to deal with adversity (as it related to potential emotion regulation) in real time across four 28-day diary bursts collected every six months. To calculate this, a two-level, hierarchical linear model was fit to each daily diary burst. Most pertinent to the present study were the significant fixed and random effects for daily stress, which indicated that individuals, on average, tended to experience higher negative affect when they were particularly stressed, and that individuals differed in terms of the strength of this relationship, respectively. Individuals’ unique affective reactivity slopes were calculated to index adaptation, with higher scores indicating worse adaptation. Using two-level, hierarchical linear modeling, we investigated the time-varying relations between two outcomes (i.e., depression and anxiety), and both individual and joint effects of adaptation (i.e., affective reactivity), reserve capacity (i.e., perceived stress reactivity), and the exposome (i.e., pandemic exposure), across the COVID-19 pandemic.

First, main effects models indicated between-person effects of adaptation, reserve capacity, and the exposome on two outcomes, such that those with lower levels of adaptation and reserve capacity (i.e., higher affective reactivity and perceived stress reactivity, respectively), or higher exposure to negative aspects of the exposome (i.e., higher negative pandemic exposure), also tended to have higher depression and anxiety (see Tables S2 and S3 for parameter estimates). There were also significant, time-varying relationships. In terms of depression, when individuals showcased particularly poor adaptation (i.e., higher affective reactivity; $\widehat{{\beta }_{20}}=2.03$, p = .0354), reported particularly low reserve capacity (i.e., higher perceived stress reactivity; $\widehat{{\beta }_{30}}=0.23$, p < .0001), and experienced particularly negative exposure to the exposome (i.e., higher negative pandemic exposure; $\widehat{{\beta }_{40}}=0.12$, p = .0024), they also tended to report higher depression. Considering anxiety, when individuals reported particularly low reserve capacity (i.e., higher perceived stress reactivity), they also tended to report worse anxiety ($\widehat{{\beta }_{30}}=0.22$, p = .0007).

A key tenet of the ADAPTOR framework is that the joint effects of adaptation, reserve capacity, and the exposome must be considered to study resilience. A three-way interaction effect among adaptation, reserve capacity, and the exposome ($\widehat{{\beta }_{80}}=0.30$, p = .0014; see Figure 3) in relation to anxiety supported this tenet. Indeed, when the exposome was markedly stressful, the relationship between anxiety and adaptation was strong and negative when reserve capacity was low, but weak when reserve capacity was high. When the exposome was less stressful, however, the relation between adaptation and anxiety was positive when reserve capacity was low, but negative when reserve capacity was high. In this way, reserve capacity may compensate for lower adaptation (and vice-versa) when individuals are faced with inordinate stress; when stress is particularly low, however, the synchrony between adaptation and reserve capacity appears beneficial. It is important to note in our example, that the characteristics of the measured exposome can affect the way in which the resilience process plays out.

Figure 3. Interaction Effect between Adaptation, Reserve Capacity, and the Exposome on Anxiety.

Note. Expected anxiety levels are plotted for prototypical individuals with 1 standard deviation above and below the mean for each predictor. When the exposome was particularly negative, higher reserve capacity buffered the negative relationship between adaptation and anxiety. When the exposome was particularly positive, a ‘match’ between levels of reserve capacity and adaptation was associated with lower time-varying anxiety levels.

As a full test of ADAPTOR, we assessed a time-varying. three-way interaction effect among the exposome, reserve capacity, and adaptation on the consequences of anxiety and depression. This approach had important strengths and limitations. One strength is our application of a longitudinal measurement burst design, which strengthens ecological validity and enabled us to assess time-varying relations among our variables. Next steps could incorporate dynamic systems analysis to allow us to tease apart different aspects of the time-varying stress regulation process (e.g., reactivity versus recovery). Although not available in our data, additional methods used to experimentally manipulate levels of stress and look at regulation would also help to explicate this process. Finally, we only included information on one indicator of each resilience component, and although our sample ranged in age across adulthood, the majority of the sample was White and college educated, which limits the generalizability of our findings; future work will determine if ADAPTOR is applicable to children, more diverse populations, and other examples adaptation, reserve capacity, exposome, and consequences.

Discussion

According to the American Psychological Association, “Resilience is the process and outcome of successfully adapting to difficult or challenging life experiences, especially through mental, emotional, and behavioral flexibility and adjustment to external and internal demands” (2022). It is noteworthy that this definition incorporates a multi-dimensional, process-oriented approach that involves using mental, emotional and behavioral reserve capacities to adapt to internal and external demands, which ultimately results in positive or negative consequences. Under the ADAPTOR framework, one can study resilience as a dynamic synergy of the bidirectional relationships among an individual’s multi-level systems, including reserve capacities, adaptational abilities and the consequences of exposure that occur in the larger context (exposome) and change over time. In doing so, we encourage researchers to conceptualize resilience by integrating systems, contexts, and timescales.

Just like theory, data collection strategies are essential to this endeavor. For example, prior research has assumed that individuals will respond to stress similarly over time and across the severity of the stressor (Rutter 2012), and only capture one assessment of the outcome or focus on between person differences instead of within person effects. Research, however, also indicates that there is heterogeneity in the stress adaptation process (Rutter 2006), and many studies indicate patterns of trajectories that represent differences in health and well-being outcomes in response to adversity. These are assumptions that must be empirically tested, and to understand this process, we must identify the stressors to which one adapts and to differentiate the reserve capacities that are needed to respond to typical, chronic or extreme conditions. Additionally, in considering the resilience process for a specific stressor, we need to remember that the context of that event is culturally, historically, and temporally embedded. Ultimately, a focus on the confluence of between- and within-person effects--interindividual differences in intraindividual change and variability--is the gold standard for this work.

There is little doubt that the next generation will demand more sophisticated research techniques to address this complexity and to accommodate the differential and multifaceted patterns of reserve capacity, adaptation and consequence. Specifically, researchers must use data collection and analytic methods that enable the examination of real-time, adaptive processes, as well as longer-term changes in these real-time processes, reserve capacities, consequences, and the exposome. Of importance to understanding resilience is that timescales matter, focusing on issues such as the cadence of the stressor, the process of dys- and reregulation, the length of the recovery period, and continuity and change in the attribute of interest. Thus, data collection methods for studying ADAPTOR must include longitudinal, multi-burst data that can detect change and fluctuations across multiple timescales, and tests of pathways or trajectories of exposure, adaptation, and change. Furthermore, given the multiplicity of consequences and reserve capacities, researchers need to consider biological, psychological, and social sources.

To accommodate these complex data structures with measurements across multiple systems, a well-thought-out and executed program of study, integrating various modeling techniques, will contribute to theory development and advance powerful insights into the determinants of the resilience process. Analytical techniques in the areas of structural equation modeling, latent class analysis, hierarchical linear growth curve modeling, dynamical systems analysis, multivariate, multilevel Rasch models, survival analysis, and quantitative genetic methodologies provide researchers with tools to assess the dynamic nature of resilience.

Because individuals and their contexts are always changing, the resilience process described here is a dynamic one (Masten, 2015). The relevant issues are broad and numerous, but we have the opportunity to answer questions such as, can one be resilient in some domains of functioning, but not others (e.g., social life, work, emotional, health)? In doing so, we need to assess multiple areas of interest for comparison. Can one be resilient today, but not a year from now? Do patterns in childhood and adolescence resilience operate at timescales that are different from later parts of the lifespan? In order to address issues of this type, longitudinal, multi-timescale data is needed. What about stress proliferation? How do stressors pile up to produce turbulent lives? How might a situation like the pandemic produce other stressors (e.g., social isolation, changes in family harmony, financial stress, or health problems) that exacerbate people’s situation and impact their ability to adapt and grow? A better understanding of the exposome, which is also dynamic, with exposures and subsequent effects varying across time, developmental stages, and timescales (Miller, 2013), is also needed. These questions, though numerous and complex, become possible to answer under the ADAPTOR framework.

Given the quantity and range of definition of the contextual influences, there are challenges to developing the concept of the exposome into a workable approach for understanding resilience research (Vrijheid, 2014). For example, how might we design valid and reliable measures of these diverse and innumerable exposures, describe and capture the psychological and biological responses to them, and then integrate the dynamic, life course nature of these influences? New tools and technologies that can address some of these challenges are being developed, and include geographical mapping (e.g., Neighborhood Atlas, including an Area Deprivation Index; https://www.neighborhoodatlas.medicine.wisc.edu/; or the National Neighborhood Data Archive, which includes amenities, grocery stores, public transit, health care, etc., https://nanda.isr.umich.edu/data/), smartphone applications (e.g., geo-tracking) and personal exposure sensors (e.g., to detect environmental toxins). Prospective, population-based cohort studies have recently started to implement these methods using the exposome framework. At the very least, we need to understand the context, source, timescale, duration, magnitude and type of stress exposure and the dynamic resources available through family, work, school, neighborhood, and the larger socio-political-culture in which these adversities are experienced. Our example, the COVID-19 pandemic, is an ongoing, worldwide stressor. With tools like geographical mapping and personal exposure sensors, we can gain an understanding of how individuals were personally affected by the pandemic, offering a more person-centered, dynamic approach. Furthermore, because these relations are dynamic, and bidirectional, individuals have the agency to select, attend to, or ignore attributes of their exposome. During the pandemic, there were also history changing cultural (e.g., the demonstrations surrounding George Floyd’s death) and socio-political (e.g., presidential election; January 6^th insurrection) events. The confluence of multiple exposures, at different proximal levels, can also be explored.

The process of resilience, especially as it relates to the exposome, broadly defined, also has important social, cultural, and political elements. Because of this, the outcomes we consider may need to extend beyond developmental impacts or mental and physical health. It could be that the consequences of the resilience process are in the eye of the beholder, and should not be predetermined a priori. Thus, ethno- or idiographic approaches to dynamic process of resilience are essential. For example, some individuals are exposed to extreme life circumstances and events, such as poverty, inequality in educational opportunities, family, neighborhood or political violence, or discrimination based on race, sexual orientation, and/or religious affiliation (Panter-Brick, 2014). The consequence of the intersectionality of this type of exposome can result in overlapping and interdependent systems of discrimination or disadvantage that, in turn, result in strategies of adaptation that lead to “positive outcomes,” but ones that are not universally recognized. As such, we cannot simply commingle resilient outcomes with positive functioning, because, for some, resilience to adversity may result in a quest for justice, power, or respect. In fact, responses to stressful situations could be deemed “maladaptive” by the collective, but are in fact useful responses to the particular exposure. Thus, goals are culturally-specific and may transcend objectives related to outcomes at the individual-level, including health and happiness (Panter-Brick & Eggerman, 2013). We need to ensure that our theories, as well as our methods and interventions, are both rigorous and comprehensive in their local relevance, while being expansive in their global reach.

Given the flexible and modifiable aspects of resilience from the ADAPTOR perspective, it is important to assess how these attributes develop and function to alleviate threat or promote resistance. As described earlier, these reserve capacities can be identified, developed and enhanced through awareness, exposure, and use. Attributes that are deemed important, but are less malleable, can be offset using compensatory strategies. For example, poor health can be improved with diet and exercise, lack of family support can be replaced with friends, neighbors, or social services, and a poor self-image can be augmented by cultural or religious traditions. At more distal levels, support agencies, protective resources, available health care, recreational opportunities, education, and other community assets can compensate for limits on available reserve capacity. By identifying periods across the lifespan when there is greater plasticity or opportunities for change, these interventions can be tailored for efficacy, and focus on individual and situational differences. Competence can build upon competence, with positive cascading effects. This information can guide intervention models, including both the targets for, and timing of, that activity. Potential strategies could include ways to 1) prevent distress by lowering levels of stress or inoculating/steeling against stress through calibrated exposures; 2) enhance resources, 3) generate positive cascades across system levels (Masten, 2019), and 4) disrupt negative ones. Beyond person-specific aspects of resilience, cultural norms, public policies and societal resources can be restructured to more responsive to the changing exposome and potentially the resulting pressures.

Questions in resilience research are complex, intricate, and diverse. Needed are metatheories like ADAPTOR that establish the dynamics that underlie the resilience process, combined with research designs and analytic strategies that provide an empirical test of the resulting propositions. Conceiving of reserve capacity as a synchrony of increases, decreases and maintenance in adaptive potential, considering adaptation as the regulation of systems perturbed by stress that uses reserve capacities to adjust, and understanding how the recovery or growth from those experiences increases reserve capacity, moves characterizations of resilience from static to dynamic. In addition, identifying windows of opportunity for interventions when developmental processes and contexts converge can also support growth in positive reserve. Longitudinal data collected across multiple timescales and contexts (see Bergeman, et al., 2020 for a more extensive discussion) transforms between-person approaches to person-oriented understandings of the ways in which people navigate stress, as well as the short- and long-term impacts of adversity. Because the way in which we conceptualize resilience is fundamental to how we design studies to examine it, issues of time scale, chronicity, subject selection, measurement, and analytic strategy are essential to putting together this intricate puzzle. Using multiple indicators of reserve capacity, adaptation and consequence across multiple timescales will help to create a deeper understanding of the multidimensional and multidirectional nature of the stressor, response and outcome, which will in turn encourage more rigorous approaches to our overall research endeavors and intervention efforts. The ultimate goal is to promote a new generation of adaptors!

Public Significance:

This paper details ‘A Dynamic Adaptational Processes Theory of Resilience (ADAPTOR),’ a novel meta-theory that incorporates several resilience conceptualizations into a developmental framework. The key argument of ADAPTOR is that individuals can ‘build’ resilience by utilizing their reserve capacities to adapt to challenging contextual factors, and that this process has long-term health consequences. An empirical example supported ADAPTOR, indicating that reserve capacity, adaptation, and contextual factors, together, predict mental health.