Lizbeth Benson and Nilam Ram
In ecological sciences, biodiversity is the dispersion of organisms across species and is used to describe the complexity of systems where species interact with each other and the environment. Some argue that biodiversity is important to cultivate and maintain because higher levels are indicative of health and resilience of the ecosystem. Because each species performs functional roles, more diverse ecosystems have greater capability to respond, maintain function, resist damage, and recover quickly from perturbations or disruptions. In the behavioral sciences, diversity-type constructs and metrics are being defined and operationalized across a variety of functional domains (socioemotional, self, cognitive, activities and environment, stress, and biological). Emodiversity, for instance, is the dispersion of an individual’s emotion experiences across emotion types (e.g., happy, anger, sad). Although not always explicitly labeled as such, many core propositions in lifespan developmental theory—such as differentiation, dedifferentiation, and integration—imply intraindividual change in diversity and/or interindividual differences in diversity. For example, socioemotional theories of aging suggest that as individuals get older, they increasingly self-select into more positive valence and low arousal emotion inducing experiences, which might suggest that diversity in positive and low arousal emotion experiences increases with age. When conceptualizing and studying diversity, important considerations include that diversity (a) provides a holistic representation of human systems, (b) differs in direction, interpretation, and linkages to other constructs such as health (c) exists at multiple scales, (d) is context-specific, and (e) is flexible to many study designs and data types. Additionally, there are also a variety of methodological considerations in study of diversity-type constructs including nuances pertaining theory-driven or data-driven approaches to choosing a metric. The relevance of diversity to a broad range of phenomena and the utility of biodiversity metrics for quantifying dispersion across categories in multivariate and/or repeated measures data suggests further use of biodiversity conceptualizations and methods in studies of lifespan development.
Li Chu, Yang Fang, Vivian Hiu-Ling Tsang, and Helene H. Fung
Cognitive processing of social and nonsocial information changes with age. These processes range from the ones that serve “mere” cognitive functions, such as recall strategies and reasoning, to those that serve functions that pertain to self-regulation and relating to others. However, aging and the development of social cognition unfold in different cultural contexts, which may assume distinct social norms and values. Thus, the resulting age-related differences in cognitive and social cognitive processes may differ across cultures. On the one hand, biological aging could render age-related differences in social cognition universal; on the other hand, culture may play a role in shaping some age-related differences. Indeed, many aspects of cognition and social cognition showed different age and culture interactions, and this makes the study of these phenomena more complex. Future aging research on social cognition should take cultural influences into consideration.
Psychoanalyst Erik Erikson was the first professional to describe and use the concept of ego identity in his writings on what constitutes healthy personality development for every individual over the course of the life span. Basic to Erikson’s view, as well as those of many later identity writers, is the understanding that identity enables one to move with purpose and direction in life, and with a sense of inner sameness and continuity over time and place. Erikson considered identity to be psychosocial in nature, formed by the intersection of individual biological and psychological capacities in combination with the opportunities and supports offered by one’s social context. Identity normally becomes a central issue of concern during adolescence, when decisions about future vocational, ideological, and relational issues need to be addressed; however, these key identity concerns often demand further reflection and revision during different phases of adult life as well. Identity, thus, is not something that one resolves once and for all at the end of adolescence, but rather identity may continue to evolve and change over the course of adult life too.
Following Erikson’s initial writings, subsequent theorists have laid different emphases on the role of the individual and the role of society in the identity formation process. One very popular elaboration of Erikson’s own writings on identity that retains a psychosocial focus is the identity status model of James Marcia. While Erikson had described one’s identity resolution as lying somewhere on a continuum between identity achievement and role confusion (and optimally located nearer the achievement end of the spectrum), Marcia defined four very different means by which one may approach identity-defining decisions: identity achievement (commitment following exploration), moratorium (exploration in process), foreclosure (commitment without exploration), and diffusion (no commitment with little or no exploration). These four approaches (or identity statuses) have, over many decades, been the focus of over 1,000 theoretical and research studies that have examined identity status antecedents, behavioral consequences, associated personality characteristics, patterns of interpersonal relations, and developmental forms of movement over time. A further field of study has focused on the implications for intervention that each identity status holds. Current research seeks both to refine the identity statuses and explore their dimensions further through narrative analysis.
Eric S. Cerino and Karen Hooker
Intraindividual variability (IIV) refers to short-term fluctuations that may be more rapid, and are often conceptualized as more reversible, than developmental change that unfolds over a longer period of time, such as years. As a feature of longitudinal data collected on micro timescales (i.e., seconds, minutes, days, or weeks), IIV can describe people, contexts, or general processes characterizing human development. In contrast to approaches that pool information across individuals and assess interindividual variability in a population (i.e., between-person variability), IIV is the focus of person-centered studies addressing how and when individuals change over time (i.e., within-person variability). Developmental psychologists interested in change and how and when it occurs, have devised research methods designed to examine intraindividual change (IIC) and interindividual differences in IIC. Dispersion, variability, inconsistency, time-structured IIV, and net IIV are distinct operationalizations of IIV that, depending on the number of measures, occasions, and time of measurement, reflect unique information about IIV in lifespan developmental domains of interest. Microlongitudinal and measurement-burst designs are two methodological approaches with intensive repeated measurement that provide a means by which various operationalizations of IIV can be accurately observed over an appropriate temporal frame to garner clearer understanding of the dynamic phenomenon under investigation. When methodological approaches are theoretically informed and the temporal frame and number of assessments align with the dynamic lifespan developmental phenomenon of interest, researchers gain greater precision in their observations of within-person variability and the extent to which these meaningful short-term fluctuations influence important domains of health and well-being. With technological advancements fueling enhanced methodologies and analytic approaches, IIV research will continue to be at the vanguard of pioneering designs for elucidating developmental change at the individual level and scaling it up to generalize to populations of interest.
Gerben J. Westerhof and Susanne Wurm
Aging is often associated with inevitable biological decline. Yet research suggests that subjective aging—the views that people have about their own age and aging—contributes to how long and healthy lives they will have. Subjective age and self-perceptions of aging are the two most studied aspects of subjective aging. Both have somewhat different theoretical origins, but they can be measured reliably. A total of 41 studies have been conducted that examined the longitudinal health effects of subjective age and self-perceptions of aging. Across a wide range of health indicators, these studies provide evidence for the longitudinal relation of subjective aging with health and longevity. Three pathways might explain this relation: physiological, behavioral, and psychological pathways. The evidence for behavioral pathways, particularly for health behaviors, is strongest, whereas only a few studies have examined physiological pathways. Studies focusing on psychological pathways have included a variety of mechanisms, ranging from control and developmental regulation to mental health. Given the increase in the number of older people worldwide, even a small positive change in subjective aging might come with a considerable societal impact in terms of health gains.
Working memory as a temporary buffer for cognitive processing is an essential part of the cognitive system. Its capacity and select aspects of its functioning are age sensitive, more so for spatial than verbal material. Assumed causes for this decline include a decline in cognitive resources (such as speed of processing), and/or a breakdown in basic control processes (resistance to interference, task coordination, memory updating, binding, and/or top-down control as inferred from neuroimaging data). Meta-analyses suggest that a decline in cognitive resources explains much more of the age-related variance in true working memory tasks than a breakdown in basic control processes, although the latter is highly implicated in tasks of passive storage. The age-related decline in working memory capacity has downstream effects on more complex aspects of cognition (episodic memory, spatial cognition, and reasoning ability). Working memory remains plastic in old age, and training in working memory and cognitive control processes yields near transfer effects, but little evidence for strong far transfer.