Steven M. Boker

Resilience Comes of Age: Defining Features in Later Adulthood

Historically, resilience research has been largely the purview of developmental investigators dealing with early childhood and adolescence. This research primarily focused on at-risk children who were exposed to significant and severe life adversities (e.g., extreme poverty, parental mental illness, community violence). The study of resilience in adulthood and later life, by comparison, remains largely understudied. In this article, we describe a program of research on adulthood resilience. We begin with a selective review of the broad literature on resilience, giving emphasis to the major approaches, empirical findings, and guiding principles that characterize prior studies. We then summarize our own approach to the phenomenon of resilience and illustrate select parts of our previous and ongoing studies of older adults. Findings from this research add to the growing body of empirical evidence suggesting that resilience is a common phenomenon that emerges from the coordinated orchestration of basic human adaptive processes.

Resilience-as-Process: Negative Affect, Stress, and Coupled Dynamical Systems

Resilience is often considered both a trait and a process. The current study proposes a new way to conceptualize resilience-as-process based on dynamical systems modeling, which allows researchers to capture the process of stress management in real time. Coupled damped linear oscillator models succinctly describe daily stress and negative affect in terms of developmental forces (e.g., velocity, acceleration). Models were fit to 56-day daily response data from 42 aging adults (M(age) = 78.8 years; SD(age) = 6.6 years) to observe and understand linkages between daily stress and affect. It was speculated that individuals with greater resilience would experience stress as less coupled to changes in negative affect (less stress reactivity), and would recover their affective equilibrium more quickly following a given exogenous stressor (greater stress recovery). To identify resilience resources related to reliable interindividual differences in coupling and damping between stress and negative affect, we examined possible protective factors. Aspects of personality and social support predicted both the strength and nature of this coupling, such that higher levels of these resources resulted in greater protection from the cost to negative affect from stress, as observed in damping of negative affect and decreased coupling between systems.

The interactive effects of estrogen and progesterone on changes in emotional eating across the menstrual cycle

Studies suggest that within-person changes in estrogen and progesterone predict changes in binge eating across the menstrual cycle. However, samples have been extremely small (maximum N = 9), and analyses have not examined the interactive effects of hormones that are critical for changes in food intake in animals. The aims of the current study were to examine ovarian hormone interactions in the prediction of within-subject changes in emotional eating in the largest sample of women to date (N = 196). Participants provided daily ratings of emotional eating and saliva samples for hormone measurement for 45 consecutive days. Results confirmed that changes in ovarian hormones predict changes in emotional eating across the menstrual cycle, with a significant estradiol × progesterone interaction. Emotional eating scores were highest during the midluteal phase, when progesterone peaks and estradiol demonstrates a secondary peak. Findings extend previous work by highlighting significant interactions between estrogen and progesterone that explain midluteal increases in emotional eating. Future work should explore mechanisms (e.g., gene-hormone interactions) that contribute to both within- and between-subjects differences in emotional eating.

Latent Differential Equation Modeling with Multivariate Multi-Occasion Indicators

In the behavioral sciences, there is increasing interest in understanding and characterizing mechanisms of developmental and behavioral processes. Measurements of multiple indicators obtained on multiple occasions on a single individual may show some intraindividual change and intraindividual variability. Process-oriented theories may predict structural patterning in these ideographic measurements. Structural equations modeling techniques can be used to test such theories by fitting confirmatory models of the implied dynamical systems to repeated observations data. The current chapter explores one method for constructing and testing confirmatory latent variable structural models in which the latent constructs (a) evolve continuously over time and (b) have linear relationships between their derivatives. The method appears to generalize well and is expected to be able to be applied to systems well beyond the simple example presented here. The chapter will begin with a rationale for studying behavioral processes from a dynamical systems perspective, introduce latent differential equations confirmatory factor models, present the results of two simulations testing the viability of this model for estimating parameters of a simple linear system, and then discuss future substantive and methodological questions that this line of modeling may address.

A dynamical systems analysis of adolescent substance abuse.

Models from dynamical systems theory were fit to the intraindividual variability In adolescent self-reported cigarette and alcohol use. A dampened linear oscillator model (potentially like a pendulum with friction) and a nonlinear oscillator model with two attractors were compared. The nonlinear oscillator model and two coupled oscillators for cigarette and alcohol use were rejected. Independent dampened linear oscillators for smoking and drinking provided high internal R(2) but were unable to account for a substantial correlation between the acceleration in cigarette usage and alcohol usage; thus evidence was found for an intrinsic self-regulation mechanism in both smoking and drinking behavior, but the hypothesis was rejected that the intrinsic mechanism leading to increases in use in one substance directly predicted increased use in the other substance. Given the hypothesis of independent linear oscillators, the sign of the dampening parameter was found to be positive, indicating a system with dynamic instability; a self-regulation mechanism in which small changes in substance use lead to amplified changes after a short period of time.

Exploring the relationship between negative urgency and dysregulated eating: etiologic associations and the role of negative affect.

Negative urgency (i.e., the tendency to engage in rash action in response to negative affect) has emerged as a critical personality trait contributing to individual differences in binge eating. However, studies investigating the extent to which genetic and/or environmental influences underlie the effects of negative urgency on binge eating are lacking. Moreover, it remains unclear whether negative urgency-binge eating associations are simply a result of the well-established role of negative affect in the development/maintenance of binge eating. The current study addresses these gaps by examining phenotypic and etiologic associations between negative urgency, negative affect, and dysregulated eating (i.e., binge eating, emotional eating) in a sample of 222 same-sex female twin pairs from the Michigan State University Twin Registry. Negative urgency was significantly associated with both dysregulated eating symptoms, even after controlling for the effects of negative affect. Genetic factors accounted for the majority (62-77%) of this phenotypic association, although a significant proportion of this genetic covariation was due to genetic influences in common with negative affect. Nonshared environmental factors accounted for a relatively smaller (23-38%) proportion of the association, but these nonshared environmental effects were independent of negative affect. Findings suggest that the presence of emotion-based rash action, combined with high levels of negative affect, may significantly increase genetic risk for dysregulated eating.

Social support as a predictor of variability: an examination of the adjustment trajectories of recent widows.

The variability pattern of emotional well-being in recent widows across a 98-day period beginning in the first month post-loss has previously been modeled by dynamical systems and shown to be an oscillating process that damps across time. The goal of the present study was to examine how variables that comprise the social support network predict characteristics of these emotional shifts in 28 recent widows. In the present study, emotional support seeking led to a steeper overall trend, whereas perceived control for social support led to a shallower overall trend. When examining intraindividual variability, instrumental support seeking predicted a slower damping rate. Understanding the individual differences in the variability patterns of recent widows is a necessary step in identifying the etiology of adjustment to widowhood.

Consequences of Continuity: The Hunt for Intrinsic Properties within Parameters of Dynamics in Psychological Processes

A little over three hundred years ago Sir Isaac Newton wrote of a simple set of relations that could be used to predict the motions of objects relative to one another. The main advantage of this insight was that the relationship between the movements of the planets and stars could be predicted much more simply than with the accurate, but cumbersome Ptolemaic calculations. But perhaps the most important consequence of the acceptance of Newtons insight was that intrinsic properties such as mass could be distinguished from measurements such as weight. The success of Newtonian mechanics led directly to the widespread use of parameters such as force, relative speed, and momentum as a way of understanding the dynamics of moving objects. A similar revolution in thinking appears to be underway in the behavioral sciences. It is likely that intensive longitudinal measurement coupled with dynamical systems analyses will lead to simplified but powerful models of the evolution of psychological processes. In this case, it is reasonable to expect that a set of intrinsic psychological properties may be able to be extracted from the parameters of successful dynamical systems models. The purpose of this article is to issue an invitation to the hunt, to provide a tentative map as to where the game might likely be found, and blow a call on the hunting horn.

Issues in intraindividual variability: Individual differences in equilibria and dynamics over multiple time scales.

This article addresses three issues germane to experimental design and statistical analysis of intraindividual variability such as the articles contained within this special section. First, the time scale of the measurement of a process can have profound effects on the outcome of analyses of the resulting time series. Measurement in time poses special problems in the design of experiments: the time scale of the measurements must be appropriate for the time scale of the process. Second, deterministic and stochastic models should be fit at the individual level and only at a second level should individual differences in parameters be modeled. Third, one must consider the possibility that nomothetic relations may be exposed by the invariance of covariance between latent variables rather than within a factor analytic measurement model.

Real-time expression cloning using appearance models

Active Appearance Models (AAMs) are generative parametric models commonly used to track, recognise and synthesise faces in images and video sequences. In this paper we describe a method for transferring dynamic facial gestures between subjects in real-time. The main advantages of our approach are that: 1) the mapping is computed automatically and does not require high-level semantic information describing facial expressions or visual speech gestures. 2) The mapping is simple and intuitive, allowing expressions to be transferred and rendered in real-time. 3) The mapped expression can be constrained to have the appearance of the target producing the expression, rather than the source expression imposed onto the target face. 4) Near-videorealistic talking faces for new subjects can be created without the cost of recording and processing a complete training corpus for each. Our system enables face-to-face interaction with an avatar driven by an AAM of an actual person in real-time and we show examples of arbitrary expressive speech frames cloned across different subjects.