Idan Shalev and Waylon J. Hastings
Stress is a multistage process during which an organism perceives, interprets, and responds to threatening environmental stimuli. Physiological activity in the nervous, endocrine, and immune systems mediates the biological stress response. Although the stress response is adaptive in the short term, exposure to severe or chronic stressors dysregulates these biological systems, promoting maladaptive physiology and an accelerated aging phenotype, including aging on the cellular level. Two structures implicated in this process of stress and cellular aging are telomeres, whose length progressively decreases with age, and mitochondria, whose respiratory activity becomes increasingly inefficient with advanced age. Stress in its various forms is suggested to influence the maintenance and stability of these structures throughout life. Elucidating the interrelated connection between telomeres and mitochondria and how different types of stressors are influencing these structures to drive the aging process is of great interest. A better understanding of this subject can inform clinical treatments and intervention efforts to reduce (or even reverse) the damaging effects of stress on the aging process.
Nancy A. Pachana, Nicola W. Burton, Deirdre McLaughlin, and Colin A. Depp
Research on healthy aging has begun to address mental health issues in later life. Despite the debates about exactly what constitutes healthy aging and which are the most useful or valid determinants of this construct to study, there is substantial evidence for several determinants of successful aging, including physical activity, cognitive stimulation, and social networks. All three of these determinants support mental health, including cognition, in later life. Resilience is another construct that plays an important role in healthy aging, but it has not received as much research attention at the end of life as in earlier periods. Factors that reduce the risk of mental distress or promote resilience with respect to mental health in the face of challenges in later life remain fruitful areas for further investigations.
Clemens Tesch-Roemer and Oliver Huxhold
Social isolation refers to the objective lack of social integration. Loneliness, in contrast, refers to the perceived lack of social integration. Loneliness has serious consequences for the well-being of aging persons. Individuals who feel lonely tend to have poorer health, less autonomy, and lower subjective well-being than individuals who do not feel lonely. Lonely individuals even tend to become more socially isolated over time. While prevalence rates of social isolation increase with advancing age, only a minority of older people suffer from severe loneliness, however. Hence, loneliness is not necessarily a consequence of growing old, but rather, depends on specific risk factors (e.g., social needs, social expectations, resources, and competencies). Interventions therefore should be focused on these risk factors (unfulfilled social needs, unmet social perceptions, and lack of resources and competencies).
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.
Jeffrey J. Lockman, Nicholas E. Fears, and Emily A. Lewis
Spatial ability is manifest across different psychological domains, including perception, action, and cognition. The development of spatial understanding originates in the perception-action skills of infants. When infants act on the world, either during object manipulation or locomotion, one may begin to glean the foundations of older children’s and adults’ efforts to think, reason, and solve problems more symbolically and abstractly. Even during infancy, different actions, such as reaching and locomotion, may incur different spatial demands, requiring infants to use spatial information flexibly. In the preschool years and beyond, as symbolic skills become more developed, children’s spatial abilities become more abstract, which are reflected in their abilities to think about the layout of environments and to use maps to learn about environments. Besides differences in spatial ability as a function of developmental level, individual differences in spatial ability have also been documented as a function of gender, daily experience, and blindness. Collectively, research on individual differences in spatial development suggests that training procedures can reduce differences in spatial skill that may arise in different individuals. Finally, to understand spatial development more fully, research is needed on the neural bases of spatial development, cross-cultural differences in spatial development, and the impact of technology on spatial behavior.
Laurence B. Leonard
Children with specific language impairment (SLI) have a significant deficit in their ability to acquire language that cannot be attributed to intellectual disability, neurological damage, hearing loss, or a diagnosis of autism. These deficits can be long-standing, and adversely affect other aspects of the affected individual’s life. There seems to be a genetic component to SLI, but the disorder is not likely to be traced to a single gene. The problem appears to be universal, but symptoms vary depending on the language being learned. Current attempts to account for SLI have increased our understanding of the most salient symptoms of the disorder, but a full understanding of SLI is not yet within reach.
Oscar Gonzalez and David P. MacKinnon
Lifespan developmental research studies how individuals change throughout their lifetime and how intraindividual or interindividual change leads to future outcomes. Lifespan researchers are interested in how developmental processes unfold and how specific developmental pathways lead to an outcome. Developmental processes have been previously studied using developmental cascade models, concepts of equifinality and multifinality, and developmental interventions. Statistical mediation analysis also provides a framework for studying developmental processes and developmental pathways by identifying intermediate variables, known as mediators, that transmit the effect between early exposures and future outcomes. The role of statistical mediation in lifespan developmental research is either to explain how the developmental process unfolds, or to identify mediators that researchers can target in interventions so that individuals change developmental pathways. The statistical mediation model is inherently causal, so the relations between the exposures, mediators, and outcomes have to be correctly specified, and ruling out alternative explanations for the relations is of upmost importance.
The statistical mediation model can be extended to deal with longitudinal data. For example, the autoregressive mediation model can represent change through time by examining lagged relations in multiwave datasets. On the other hand, the multilevel mediation model can deal with the clustering of repeated measures within individuals to study intraindividual and interindividual change. Finally, the latent growth curve mediation model can represent the variability of linear and nonlinear trajectories for individuals in the variables in the mediation model through time. As a result, developmental researchers have access to a range of models that could describe the theory of change they want to study. Researchers are encouraged to consider mechanisms of change and to formulate mediation hypotheses about lifespan development.
Agus Surachman and David M. Almeida
Stress is a broad and complex phenomenon characterized by environmental demands, internal psychological processes, and physical outcomes. The study of stress is multifaceted and commonly divided into three theoretical perspectives: social, psychological, and biological. The social stress perspective emphasizes how stressful life experiences are embedded into social structures and hierarchies. The psychological stress perspective highlights internal processes that occur during stressful situations, such as individual appraisals of the threat and harm of the stressors and of the ways of coping with such stressors. Finally, the biological stress perspective focuses on the acute and long-term physiological changes that result from stressors and their associated psychological appraisals. Stress and coping are inherently intertwined with adult development.
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.
Stephen J. Bright
In the 21st century, we have seen a significant increase in the use of alcohol and other drugs (AODs) among older adults in most first world countries. In addition, people are living longer. Consequently, the number of older adults at risk of experiencing alcohol-related harm and substance use disorders (SUDs) is rising. Between 1992 and 2010, men in the United Kingdom aged 65 years or older had increased their drinking from an average 77.6 grams to 97.6 grams per week. Data from Australia show a 17% increase in risky drinking among those 60–69 between 2007 and 2016. Among Australians aged 60 or older, there was a 280% increase in recent cannabis use from 2001 to 2016. In the United States, rates of older people seeking treatment for cocaine, heroin, and methamphetamine have doubled in the past 10 years. This trend is expected to continue.
Despite these alarming statistics, this population has been deemed “hidden,” as older adults often do not present to treatment with the SUD as a primary concern, and many healthcare professionals do not adequately screen for AOD use. With age, changes in physiology impact the way we metabolize alcohol and increase the subjective effects of alcohol. In addition, older adults are prone to increased use of medications and medical comorbidities. As such, drinking patterns that previously would have not been considered hazardous can become dangerous without any increase in alcohol consumption. This highlights the need for age-specific screening of all older patients within all healthcare settings.
The etiology of AOD-related issues among older adults can be different from that of younger adults. For example, as a result of issues more common as one ages (e.g., loss and grief, identity crisis, and boredom), there is a distinct cohort of older adults who develop SUDs later in life despite no history of previous problematic AOD use. For some older adults who might have experimented with drugs in their youth, these age-specific issues precipitate the onset of a SUD. Meanwhile, there is a larger cohort of older adults with an extensive history of SUDs. Consequently, assessments need to be tailored to explore the issues that are unique to older adults who use AODs and can inform the development of age-specific formulations and treatment plans. In doing so, individualized treatments can be delivered to meet the needs of older adults. Such treatments must be tailored to address issues associated with aging (e.g., reduced mobility) and may require multidisciplinary input from medical practitioners and occupational therapists.
John W. Rowe and Dawn C. Carr
While the factors that influence the well-being of individuals in late life have long been a major concern of research in aging, they have been a particularly active area of research and debate since the 1980s and continue to have a prominent role in gerontological research and debate. Early research on aging (from the 1920s to the 1960s) focused largely on examining typical problems that come with aging. The term successful aging was initially used to describe those who aged better than expected. In the 1980s, the MacArthur Network on Successful Aging, concerned that the field of gerontology had become preoccupied with disease and disability to the neglect of studies of the factors that fostered doing well in late life, conducted a series of studies of high-performing older persons and formulated the MacArthur theory of successful aging, which included three principal components: avoidance of disease, maintenance of physical and cognitive function, and engagement with society. Since its initial publication, the concept of successful aging has been applied to many subpopulations of older persons based on geography (East vs. West), socioeconomic status, race and ethnicity, religion, cognitive or physical function, and disease states.
Kim Van Orden, Caroline Silva, and Yeates Conwell
Suicide in later life is a significant public health problem around the world—a problem that will increase in magnitude in the coming years with the impact of population aging. Adults age 70 and older have higher suicide rates than younger groups worldwide in both lower-income and higher-income countries. While suicide rates tend to increase with age, suicide in later life is not an expected or normative response to stressors that accompany the aging process. Instead, a constellation of risk factors places an older adult at elevated risk for suicide. These factors can be remembered as the Five D’s: psychiatric illness (primarily
Sara J. Czaja and Chin Chin Lee
The expanding power of computers and the growth of information technologies such as the Internet have made it possible for large numbers of people to have direct access to an increasingly wide array of information sources and services. Use of technology has become an integral component of work, education, communication, entertainment, and health care. Moreover, home appliances, security systems, and other communication devices are becoming more integrated with network resources providing faster and more powerful interactive services. Older adults represent an increasing large proportion of the population and will need to be active users of technology to function independently and receive the potential benefits of technology. Thus, it is critically important to understand how older adults respond to and adopt new information technologies. Technology offers many potential benefits for older people such as enhanced access to information and resources and health-care services, as well as opportunities for cognitive and social engagement. Unfortunately, because of a number of factors many older people confront challenges and barriers when attempting to access and use technology systems.
Life is filled with goals or intentions that people hope to realize. Some of these are rather mundane (e.g., remembering to purchase a key ingredient for a recipe when stopping at the market), while others are more significant (e.g., remembering to pick up one’s child from school at the end of the day). Prospective memory represents the ability to form and then realize intentions at an appropriate time. A fundamental aspect of prospective memory is that one is engaged in one or more tasks (i.e., ongoing activities) between the formation of an intention and the opportunity to realize the goal. For instance, in the shopping example, one might form the intention at home and then travel to the market and collect several other items before walking past the desired ingredient. Considerable research has demonstrated that the efficiency of prospective memory declines with age, although age-related differences are not universal.
The neurocognitive processes underpinning age-related differences in the formation and realization of delayed intentions have been investigated in studies using event-related brain potentials. This research reveals that age-related differences in prospective memory arise from the disruption of neural systems supporting the successful encoding of intentions, the detection of prospective memory cues, and possibly processes supporting the retrieval of intentions from memory when a cue is encountered or efficiently shifting from the ongoing activity to the prospective element of the task. Therefore, strategies designed to ameliorate age-related declines in prospective memory should target a variety of processes engaged during the encoding, retrieval, and enactment of delayed intentions.
Theoretical Perspectives on Age Differences in Brain Activation: HAROLD, PASA, CRUNCH—How Do They STAC Up?
Sara B. Festini, Laura Zahodne, and Patricia A. Reuter-Lorenz
Cognitive neuroimaging studies often report that older adults display more activation of neural networks relative to younger adults, referred to as overactivation. Greater or more widespread activity frequently involves bilateral recruitment of both cerebral hemispheres, especially the frontal cortex. In many reports, overactivation has been associated with superior cognitive performance, suggesting that this activity may reflect compensatory processes that offset age-related decline and maintain behavior. Several theories have been proposed to account for age differences in brain activation, including the Hemispheric Asymmetry Reduction in Older Adults (HAROLD) model, the Posterior-Anterior Shift in Aging (PASA) theory, the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH), and the Scaffolding Theory of Aging and Cognition (STAC and STAC-r). Each model has a different explanatory scope with regard to compensatory processes, and each has been highly influential in the field. HAROLD contrasts the general pattern of bilateral prefrontal activation in older adults with that of more unilateral activation in younger adults. PASA describes both anterior (e.g., frontal) overactivation and posterior (e.g., occipital) underactivation in older adults relative to younger adults. CRUNCH emphasizes that the level or extent of brain activity can change in response to the level of task demand at any age. Finally, STAC and STAC-r take the broadest perspective to incorporate individual differences in brain structure, the capacity to implement functional scaffolding, and life-course neural enrichment and depletion factors to predict cognition and cognitive change across the lifespan. Extant empirical work has documented that compensatory overactivation can be observed in regions beyond the prefrontal cortex, that variations in task difficulty influence the degree of brain activation, and that younger adults can show compensatory overactivation under high mental demands. Additional research utilizing experimental designs (e.g., transcranial magnetic stimulation), longitudinal assessments, greater regional precision, both verbal and nonverbal material, and measures of individual difference factors will continue to refine our understanding of age-related activation differences and adjudicate among these various accounts of neurocognitive aging.
Well-being is a core concept for both individuals, groups and societies. Greater understanding of trajectories of well-being in later life may contribute to the achievement and maintenance of well-being for as many as possible. This article reviews two main approaches to well-being: hedonic and eudaimonic well-being, and shows that it is not chronological age per se, but various factors related to age that underlie trajectories of well-being at older ages. Next to the role of genes, heritability and personality traits, well-being is determined to a substantial extent by external circumstances and resources (e.g., health and social relationships), and to malleable individual behaviors and beliefs (e.g., self-regulatory ability and control beliefs). Although many determinants have been identified, it remains difficult to decide which of them are most important. Moreover, the role of some determinants varies for different indicators of well-being, such as positive affect and life satisfaction. Several prominent goal- and need-based models of well-being in later life are discussed, which explicate mechanisms underlying trajectories of well-being at older ages. These are the model of Selection, Optimization, and Compensation, the Motivational Theory of Lifespan Development, Socio-emotional Selectivity Theory, Ryff’s model of Psychological Well-Being, Self-Determination Theory, and Self-Management of Well-being theory. Also, interventions based on these models are reviewed, although not all of them address older adults. It is concluded that the literature on well-being in later life is enormous, and, together with various conceptual models, offers many important insights. Still, the field would benefit from more theoretical integration, and from more attention to the development and testing of theory-based interventions. This remains a challenge for the science of well-being in later life, and could be an important contribution to the well-being of a still growing proportion of the population.
David J. Madden and Zachary A. Monge
Age-related decline occurs in several aspects of fluid, speed-dependent cognition, particularly those related to attention. Empirical research on visual attention has determined that attention-related effects occur across a range of information processing components, including the sensory registration of features, selection of information from working memory, controlling motor responses, and coordinating multiple perceptual and cognitive tasks. Thus, attention is a multifaceted construct that is relevant at virtually all stages of object identification. A fundamental theme of attentional functioning is the interaction between the bottom-up salience of visual features and top-down allocation of processing based on the observer’s goals. An underlying age-related slowing is prominent throughout visual processing stages, which in turn contributes to age-related decline in some aspects of attention, such as the inhibition of irrelevant information and the coordination of multiple tasks. However, some age-related preservation of attentional functioning is also evident, particularly the top-down allocation of attention. Neuroimaging research has identified networks of frontal and parietal brain regions relevant for top-down and bottom-up attentional processing. Disconnection among these networks contributes to an age-related decline in attention, but preservation and perhaps even increased patterns of functional brain activation and connectivity also contribute to preserved attentional functioning.
Human visual development is a complex dynamic psychological/neurobiological process, being part of the developing systems for cognition, action, and attention. This article reviews current knowledge and methods of study of human visual development in infancy and childhood, in relation to typical early visual brain development, and how it can change in developmental disorders, both acquired (e.g., related to at-risk births) and genetic disorders. The newborn infant starts life with a functioning subcortical visual system which controls newborn orienting to nearby high contrast objects and faces. Although visual cortex may be active from birth, its characteristic stimulus selectivity and control of visual responses is generally seen to emerge around six to twelve weeks after birth. By age six months the infant has adequate acuity and contrast sensitivity in nearby space, and operating cortical mechanisms for discriminating colors, shapes, faces, movement, stereo depth, and distance of objects, as well as the ability to focus and shift attention between objects of interest. This may include both feedforward and feedback pathways between cortical areas and between cortical and subcortical areas. Two cortical streams start to develop and become interlinked, the dorsal stream underpinning motion, spatial perception and actions, and the ventral stream for recognition of objects and faces. The neural systems developing control and planning of actions include those for directed eye movements, reaching and grasping, and the beginnings of locomotion, with these action systems being integrated into the other developing subcortical and cortical visual networks by one year of age. Analysis of global static form (pattern) and global motion processing allows the development of dorsal and ventral streams to be monitored from infancy through childhood. The development of attention, visuomotor control and spatial cognition in the first years show aspects of function related to the developing dorsal stream, and their integration with the ventral stream.
The milestones of typical visual development can be used to characterize visual and visuo-cognitive disorders early in life, such as in infants with perinatal brain injuries and those born very prematurely. The concept of “dorsal stream vulnerability” is outlined. It was initially based on deficits in global motion sensitivity relative to static form sensitivity, but can be extended to the planning and execution of visuomotor actions and problems of attention, together with visuospatial and numerical cognition. These problems are found in the phenotype of children with both genetic developmental disorders (e.g., Williams syndrome, autism, fragile-X, and dyslexia), and in acquired developmental disorders related to very preterm birth, or in children with abnormal visual input such as congenital cataract, refractive errors, or amblyopia. However, there are subtle differences in the manifestation of these disorders which may also vary considerably across individuals. Development in these clinical conditions illustrates the early, but limited, plasticity of visual brain mechanisms, and provides a challenge for the future in designing successful intervention and treatment.
Ekaterina Zavershneva and René van der Veer
Lev Semyonovich Vygotsky (real name Lev Simkhovich Vygodsky; Orsha 1896–Moscow 1934) was a Russian psychologist who created cultural-historical theory, which proved influential in developmental psychology and other psychological disciplines. Vygotsky characterized his approach as “height psychology” (as opposed to “depth psychology”) and posited that the higher forms of mind should be the starting point for the study of human development. In his view it was essential to study psychological processes in their historical dynamics; these dynamics could be unraveled with the causal-genetic approach he developed, which involved the guided formation of mind in the course of its study or the experimental unfolding of ontogeny. Vygotsky claimed that the mechanisms of human development are not genetically determined and that we must find its source in culture and the social environment. Human development is mediated by cultural artifacts and sign systems, which are mastered in a dialogue with other people in spontaneous or guided interaction, which stimulates development by creating a zone of proximal development. The major means of the transformation of innate mind into higher mind is language, which enables us to preserve and transmit the experience of generations. In this process of cultural development the person develops a system of higher psychological functions that are social in origin, voluntary and mediated in nature, and form part of a systemic whole. The process of ontogeny goes through a series of stable periods and crises that correspond with specific conditions of the social situation of development and the developmental tasks. Age periods are completed with the development of neoformations, which do not just form results but are also prerequisites for further development. With the development of verbal thinking and the mastery of cultural means of behavior the person masters her/his innate mind and becomes a personality, whose main characteristic is freedom of behavior.
In the literature of mainstream scientific psychology, German scholar William Stern has been known primarily (if at all) as the inventor of the intelligence quotient (IQ). In fact, however, Stern’s contributions to psychology were much greater and more consequential than this. In this all-inclusive article, I have sought to provide readers with a fuller appreciation for the breadth and depth of Stern’s work, and, in particular, for that comprehensive system of thought that he elaborated under the name “critical personalism.” Drawing frequently on translated quotations from Stern’s published works, and on his personal correspondence with the Freiburg philosopher Jonas Cohn, I have endeavored to show how Stern was much more than “the IQ guy.” During the first 20 years of his academic career, spent at the University of Breslau in what is now the Polish city of Wroclaw, Stern founded that sub-discipline of psychology that would be concentrated on the study of individual differences in various aspects of human psychological functioning. He also made major contributions to that sub-discipline referred to at the time as “child” psychology, and laid the foundations for a comprehensive system of thought that he would name “critical personalism.” After relocating to Hamburg in 1916, Stern continued his scholarly efforts in these domains, taught courses both in psychology and in philosophy at the university that opened its doors there in 1919, and played major administrative roles there in the institutional homes of both disciplines until forced to flee Nazi Germany in 1934. The present chapter highlights ways in which, over the course of his scholarly career, Stern boldly opposed certain trends within mainstream thinking that were ascendant during his time.