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.
S.P.J. van Alphen and S.M.J. Heijnen-Kohl
Personality disorders severely impact a person’s functioning in many ways. Although a person may have found ways to cope throughout life, at an older age underlying dysfunctional patterns can emerge and cause much distress both for the person and those around them. Why normal personality traits shift to abnormality is not easily understood. In literature there are many theories with different definitions. In this chapter a few of the prominent theories on the description of personality will be discussed. For example, some psychologists have described personality as a complex pattern that is deeply tied to psychological characteristics that are largely unaware, hard to wipe out, and expressed in all aspects of functioning. Other psychologists define personality as individual differences in the tendency to display consistent patterns of thoughts, feelings, and behaviors. The American Psychiatric Association (2013) defines personality traits as enduring patterns in the way someone perceives, relates to, and thinks about the environment and oneself and that these patterns are exhibited in a wide range of social and personal context. These definitions of personality are all concerned with unique and stable characteristics in different situations. These theories are not age-specific, but age-related changes and differences in manifestations do occur. This complicates diagnosis as measurements for older adults have barely been developed or validated. The feasibility of measurements and various information sources will be addressed. Descriptions and diagnosis have the ability to enhance treatment for patients with personality disorders. Known treatment forms have successfully been applied to older adults as well and differing treatment levels will be distinguished. Treatment of first choice can be aimed at changing personality characteristics or enhancing adaptation, but in some cases supportive treatment is the best fit. In clinical practice a variety of possible interventions is needed to provide the best care for different manifestations of personality disorders.
Cornelia Wrzus and Jenny Wagner
Over the entire life span, social relationships are essential ingredients of human life. Social relationships describe regular interactions with other people over a certain period and generally include a mental representation of the relationship and the relationship partner. Social relationships cover diverse types, such as those with family members, romantic partners, friends, colleagues, as well as with other unrelated people. In general, most of these relationships change in number, contact frequency, and relationship quality during adulthood and old age. For example, both the number of and contact with friends and other unrelated people generally decrease with advancing age, whereas the number of and contact with family members remain rather stable. Relatively little is known about longitudinal changes in the quality of relationships, apart from romantic relationships, because few longitudinal studies have tracked specific relationships. Some explanatory factors, which are discussed in the literature, are (a) motivational changes, (b) reduced time due to work and family demands during adulthood, and (c) resource constraints in older age. Future work on social relationships would benefit from increasingly applying dyadic and network approaches to include the perspective of relationship partners as well as from examining online and offline contact in social relationships, which has already proved important among younger adults.
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.