Megan S. Barker, Emily C. Gibson, and Gail A. Robinson
The term “acquired brain injury” refers to any type of brain damage that occurs after birth. Two main types of acquired brain injury are stroke and traumatic brain injury (TBI). A stroke occurs when there is a blockage or bleed in the vascular system of the brain, while a TBI results from an external force to the head. Older adults are at a higher risk of both stroke and TBI; thus, overall incidence is increasing as the proportion of older adults in the population is growing. Stroke and TBI result in immediate and long-term cognitive changes. Impairments in the domains of language, attention, memory, executive functions, perception, and social cognition have been documented following stroke and TBI. However, strokes tend to cause focal or selective cognitive disorders, while cognitive deficits following TBI are widespread and can be generalized. Individuals who have suffered a stroke or TBI may also experience psychosocial changes; for example, symptoms of depression and anxiety are common. Functional outcomes, including independence in activities, are varied and are associated with a range of factors including age, injury severity, cognitive disorders, and psychosocial factors. To achieve optimal outcomes for individuals following stroke and TBI, and to reduce the impact of the injury on everyday functioning, a multidisciplinary rehabilitation process is recommended.
Jack Kuhns and Dayna R. Touron
The study of aging and cognitive skill learning is concerned with age-related changes and differences in how we gather, store, and use information and abilities. As life expectancy continues to rise, resulting in greater numbers and proportions of older individuals in the population, understanding the development and retention of skills across the lifespan is increasingly important. Older adults’ task performance in cognitive skill learning is often equal to that of young adults, albeit not as efficient, where older adults often require more time to complete training. Investigations of age differences in fundamental cognitive processes of attention, memory, or executive functioning generally reveal declines in older adults. These are related to a slowing of cognitive processing. Slowing in cognitive processing results in longer time necessary to complete tasks which can interfere with the fidelity of older adults’ cognitive processes in time-limited scenarios. Despite this, older adults maintain comparable rates of learning with young adults, albeit with some reduced efficiency in more complex tasks. The effectiveness of older adults’ learning is also impacted by a lesser tendency to recognize and adopt efficient learning strategies, as well as less flexibility in strategy use relative to younger adults. In learning tasks that involve a transition from using a complex initial strategy to relying on memory retrieval, older adults show a volitional avoidance of memory that is related to lower memory confidence and an impoverished mental model of the task. Declines in learning are not entirely problematic from a functional perspective, however, as older adults can often rely upon their extensive knowledge to compensate for certain deficiencies, particularly in everyday tasks. Indeed, domains where older adults have maintained expertise are somewhat insulated from other age-related declines.
Aidan Moran and John Toner
We are constantly bombarded by information. Therefore, during every waking moment of our lives, we face decisions about which stimuli to prioritize and which ones to ignore. To complicate matters, the information that clamors for our attention includes not only events that occur in the world around us but also experiences that originate in the subjective domain of our own thoughts and feelings. The end result is that our minds can consciously attend to only a fraction of the rich kaleidoscope of information and experiences available to us from our senses, thoughts, memories, and imagination. Attentional processes such as “concentration,” or the ability to focus on the task at hand while ignoring distractions, are crucial for success in sport and other domains of skilled performance. To illustrate, Venus Williams, one of the greatest tennis players of all time, proclaimed that “for the players it is complete and pure focus. You don’t see anything or hear anything except the ball and what’s going on in your head.” For psychological scientists, concentration resembles a mental spotlight (like the head-mounted torch that miners and divers wear in dark environments) that illuminates targets located either in the external world around us or in the internal world of our subjective experiences. A major advantage of this spotlight metaphor is that it shows us that concentration is never “lost”—although it can be diverted to targets (whether in the external world or inside our heads) that are irrelevant to the task at hand. Research on attentional processes in sport and performance has been conducted in cognitive psychology (the study of how the mind works), cognitive sport psychology (the study of mental processes in athletes), and cognitive neuroscience (the study of how brain systems give rise to mental processes). From this research, advances have been made both in measuring attentional processes and in understanding their significance in sport and performance settings. For example, pupillometry, or the study of changes in pupil diameter as a function of cognitive processing, has been used as an objective index of attentional effort among skilled performers such as musicians and equestrian athletes. Next, research suggests that a heightened state of concentration (i.e., total absorption in the task at hand) is crucial to the genesis of “flow” states (i.e., rare and elusive moments when everything seems to come together for the performer) and optimal performance in athletes. More recently, studies have shown that brief mindfulness intervention programs, where people are trained to attend non-judgmentally to their own thoughts, feelings, and sensations, offer promise in the quest to enhance attentional skills in elite athletes. By contrast, anxiety has been shown to divert skilled performers’ attention to task-irrelevant information—sometimes triggering “choking” behavior or the sudden and significant deterioration of skilled performance. Finally, concentration strategies such as “trigger words” (i.e., the use of short, vivid, and positively phrased verbal reminders such as “this ball now”) are known to improve athletes’ ability to focus on a specific target or to execute skilled actions successfully.
Ye In (Jane) Hwang, Kitty-Rose Foley, Samuel Arnold, and Julian Trollor
Autism spectrum disorder (ASD), or autism, is a neurodevelopmental disorder that is typically recognized and diagnosed in childhood. There is no established biological marker for autism; rather, the diagnosis is made based on observation of behavioral traits, including (a) persistent deficits in social interaction and communication, and (b) restricted, repetitive patterns of behavior, interests, or activities. Because autism is a spectrum disorder, autistic individuals are a highly heterogeneous group and differ widely in the presentation and severity of their symptoms. The established prevalence of ASD is approximately 1% of the population.
Information about autism in adulthood is limited; most of the literature examines childhood and adolescence. While the term “later life” has traditionally been associated with those over the age of 65, a dire lack of understanding exists for those on the autism spectrum beyond early adulthood.
Individuals remain on the spectrum into later life, though some mild improvements in symptoms are observed over time. Autistic adults experience high levels of physical and mental health comorbidities. Rates of participation in employment and education are also lower than that of the general population. Quality of life is reportedly poorer for autistic adults than for nonautistic peers, though this is not affected by age. More robust studies of the health, well-being, and needs of autistic adults are needed, especially qualitative investigations of adulthood and aging and longitudinal studies of development over the lifespan.
Anne Josephine Dutt, Hans-Werner Wahl, and Manfred Diehl
The term Awareness of Aging (AoA) incorporates all aspects of individuals’ perceptions, behavioral experiences, and subjective interpretations related to their process of growing older. In this regard, AoA goes beyond objective descriptions of the aging process, such as calendar age or biological age. Commonly used AoA constructs referring to the ongoing experience of the aging process encompass concepts such as subjective age, attitudes toward one’s own aging, self-perceptions of aging, and awareness of age-related change. AoA also incorporates elements that are more pre-conscious in nature, such as age stereotypes and culturally held notions about the aging process. Despite their theoretically broad common foundation, AoA constructs differ according to their specific frames of reference, such as whether and how they take into account the multidimensionality and multi-directionality of development. Examining the existing body of empirical work identifies several antecedents of AoA, such as sociodemographic “background” variables, physical health and physical functioning, cognition, psychological well-being and mental health, psychological variables (e.g., personality, anxiety), and life events. In general, more positive manifestations on these variables are accompanied by a more positive perception and evaluation of the aging process. Moreover, AoA is longitudinally linked to important developmental outcomes, such as health, cognition, subjective well-being, and mortality. Overall, the study of AoA has developed as a promising area of psychological aging research that has grown in its conceptual and empirical rigor during recent years.
Karen Z. H. Li, Halina Bruce, and Rachel Downey
Research on the interplay of cognition and mobility in old age is inherently multidisciplinary, informed by findings from life span developmental psychology, kinesiology, cognitive neuroscience, and rehabilitation sciences. Early observational work revealed strong connections between sensory and sensorimotor performance with measures of intellectual functioning. Subsequent work has revealed more specific links between measures of cognitive control and gait quality. Convergent evidence for the interdependence of cognition and mobility is seen in patient studies, wherein cognitive impairment is associated with increased frequency and risk of falling. Even in cross-sectional studies involving healthy young and older adults, the effects of aging on postural control and gait are commonly exacerbated when participants perform a motor task with a concurrent cognitive load. This motor-cognitive dual-task method assumes that cognitive and motor domains compete for common capacity, and that older adults recruit more cognitive capacity than young adults to support gait and posture.
Neuroimaging techniques such as magnetic resonance imaging (MRI) have revealed associations between measures of mobility (e.g., gait velocity and postural control) and measures of brain health (e.g., gray matter volumes, cortical thickness, white matter integrity, and functional connectivity). The brain regions most often associated with aging and mobility also appear to subserve high-level cognitive functions such as executive control, attention, and working memory (e.g., dorsolateral prefrontal cortex, anterior cingulate). Portable functional neuroimaging has allowed for the examination of neural functioning during real-time walking, often in conjunction with detailed spatiotemporal measures of gait. A more recent strategy that addresses the interdependence of cognitive and motor processes in old age is cognitive remediation. Cognitive training has yielded promising improvements in balance, walking, and overall mobility status in healthy older adults, and those with age-related neurodegenerative conditions such as Parkinson’s Disease.
Skylar M. Brannon and Bertram Gawronski
The desire to maintain consistency between cognitions has been recognized by many psychologists as an important human motive. Research on this topic has been highly influential in a variety of areas of social cognition, including attitudes, person perception, prejudice and stereotyping, and self-evaluation. In his seminal work on cognitive dissonance, Leon Festinger noted that inconsistencies between cognitions result in negative affect. Further, he argued that the motivation to maintain consistency is a basic motive that is intrinsically important. Subsequent theorists posed revisions to Festinger’s original theory, suggesting that consistency is only important to the extent that it allows one to maintain a desired self-view or to communicate traits to others. According to these theorists, the motivation to maintain consistency serves as a means toward a superordinate motive, not as an end in itself. Building on this argument, more recent perspectives suggest that consistency is important for the execution of context-appropriate action and the acquisition and validation of knowledge.
Several important lines of research grew out of the idea that cognitive consistency plays a central role in social information processing. One dominant line of research has aimed toward understanding how people deal with inconsistencies between their attitudes and their behaviors. Other research has investigated how individuals maintain their beliefs either by (1) avoiding exposure to contradictory information or (2) engaging in cognitive processes aimed toward reconciling an inconsistency after being exposed to contradictory information. Cognitive consistency perspectives have also been leveraged to understand (1) the conditions under which explicit and implicit evaluations correlate with one another, (2) when change in one type of evaluation corresponds with change in the other, and (3) the roles of distinct types of consistency principles underlying explicit and implicit evaluations.
Expanding on these works, newer lines of research have provided important revisions and extensions to early research on cognitive consistency, focusing on (1) the identification of inconsistency, (2) the elicitation of negative affect in response to inconsistency, and (3) behavioral responses aimed to restore inconsistency or mitigate the negative feelings arising from inconsistency. For example, some research has suggested that, instead of following the rules of formal logic, perceptions of (in)consistency are driven by “psycho-logic” in that individuals may perceive inconsistency when there is logical consistency, and vice versa. Further, reconciling conflicting research on the affective responses to inconsistency, recent work suggests that all inconsistencies first elicit negative affect, but immediate affective reactions may change in line with the hedonic experience of the event when an individual has time to make sense of the inconsistency. Finally, new frameworks have been proposed to unite a broad range of phenomena under one unifying umbrella, using the concept of cognitive consistency as a common denominator.
Benjamin Boller and Sylvie Belleville
Individuals with mild cognitive impairment (MCI) experience cognitive difficulties and many find themselves in a transitional stage between aging and dementia, making this population a suitable target for cognitive intervention. In MCI, not all cognitive functions are impaired and preserved functions can thus be recruited to compensate for the impact of cognitive impairment. Improving cognition may have a tremendous impact on quality of life and help delay the loss of autonomy that comes with dementia. Several studies have reported evidence of cognitive benefits following cognitive intervention in individuals with MCI. Studies that relied on training memory and attentional control have provided the most consistent evidence for cognitive gains. A few studies have investigated the neurophysiological processes by which these training effects occur. More research is needed to draw clear conclusions on the type of brain processes that are engaged in cognitive training and there are insufficient findings regarding transfer to activities of daily life. Results from recent studies using new technologies such as virtual reality provide encouraging evidence of transfer effects to real-life situations.
Aleksandra Kudlicka and Linda Clare
The number of people living with dementia is growing, and with limited pharmacological treatment options the importance of psychosocial interventions is increasingly recognized. Cognitive rehabilitation is particularly well placed to address the needs of people living with mild and moderate dementia and their family supporters, as it offers a range of tools to tackle the complexity of the condition. It utilizes powerful approaches of problem solving and goal setting combined with evidence-based rehabilitative techniques for managing cognitive impairments. It also incorporates strategies to address emotional and motivational aspects of dementia that may affect a person’s well-being. It is provided on an individual basis, usually in people’s homes, making it directly applicable to everyday life. It is also genuinely person-centered and flexible as the therapy goals are agreed in a collaborative process between the therapist, person with dementia, and family members. Cognitive rehabilitation does not claim to address underlying pathology, but instead focuses on a person’s functional ability and enjoyment of life.
Evidence for effectiveness of cognitive rehabilitation in the context of mild and moderate dementia, mostly Alzheimer’s disease (AD), is gradually accumulating with a number of randomized control trials demonstrating that people with mild and moderate dementia can significantly improve their functioning in targeted areas. For example, the GREAT trial with 475 people with mild to moderate Alzheimer’s, vascular, and mixed dementia completed in 2017 in the United Kingdom demonstrated that cognitive rehabilitation improves everyday functioning in relation to individual therapy goals.
There is a growing interest in cognitive rehabilitation and the focus shifts to extending evidence to less-common forms of dementia, particularly in people with non-amnestic presentation. Future efforts need to concentrate on promoting the approach and optimizing application in real-life settings with the aim of maximizing benefits for people living with dementia and their families.
Michael J. Valenzuela
Cognitive reserve refers to the many ways that neural, cognitive, and psychosocial processes can adapt and change in response to brain aging, damage, or disease, with the overarching effect of preserving cognitive function. Cognitive reserve therefore helps to explain why cognitive abilities in late life vary as dramatically as they do, and why some individuals are brittle to degenerative pathology and others exceptionally resilient. Historically, the term has evolved and at times suffered from vague, circular, and even competing notions. Fortunately, a recent broad consensus process has developed working definitions that resolve many of these issues, and here the evidence is presented in the form of a suggested Framework: Contributors to cognitive reserve, which include environmental exposures that demand new learning and intellectual challenge, genetic factors that remain largely unknown, and putative G × E interactions; mechanisms of cognitive reserve that can be studied at the biological, cognitive, or psychosocial level, with a common theme of plasticity, flexibility, and compensability; and the clinical outcome of (enriched) cognitive reserve that can be summarized as a compression of cognitive morbidity, a relative protection from incident dementia but increased rate of progression and mortality after diagnosis. Cognitive reserve therefore has great potential to address the global challenge of aging societies, yet for this potential to be realized a renewed scientific, clinical, and societal focus will be required.
Alison Chasteen, Maria Iankilevitch, Jordana Schiralli, and Veronica Bergstrom
In 2016, Statistics Canada released the results of the most recent census. For the first time ever, the proportion of Canadians aged 65-plus years surpassed the proportion aged 15 and under. The increase in the proportion of older adults was viewed as further evidence of the faster rate of aging of Canada’s population. Such demographic shifts are not unique to Canada; many industrialized nations around the world are experiencing similar changes in their populations. Increases in the older adult population in many countries might produce beneficial outcomes by increasing the potential for intergenerational contact and exposure to exemplars of successful aging. Such positive intergenerational contact could counter prevailing age stereotypes and improve intergenerational relations. On the other hand, such increases in the number of older adults could be viewed as a strain and potential threat to resources shared with younger age groups. The possibility of increased intergenerational conflict makes it more important than ever before to understand how older adults are stereotyped, how those stereotypes can produce different kinds of biased behavior toward them, and what the impact of those stereotypes are on older adults themselves.
Social-cognitive age representations are complex and multifaceted. A common stereotype applied to older people is one of warmth but incompetence, often resulting in paternalistic prejudice toward them. However, such benevolent prejudice, characterized by warm overtones, can change to hostile bias if older adults are perceived to violate prescriptive norms about age-appropriate behavior. In addition to coping with age prejudice, older adults also have to deal with the deleterious effects of negative age stereotypes on their day-to-day function. Exposure to negative aging stereotypes can worsen older adults’ cognitive performance in a number of contexts. As well, age stereotypes can be incorporated into older adults’ own views of aging, also leading to poorer outcomes for them in a variety of domains. A number of interventions to counteract the effects of negative aging stereotypes appear promising, but more work remains to be done to reduce the impact of negative aging stereotypes on daily function in later life.
Michael Cole and Martin Packer
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Psychology. Please check back later for the full article.
There is a growing appreciation of the importance of understanding the role of culture in children’s psychological development (also called human ontogenesis). In particular, the texts of Lev Vygotsky contributed greatly to a “cultural psychology” in which the study of culture and development is seen as central. At the same time, cross-cultural research in psychology has paid growing attention to developmental issues. Although there continues to be much debate over how to define culture, it is generally agreed that different human social groups have distinct cultures. It is common to assume, in addition, that cultural differences lead to differences in the trajectories of children’s development. This is true, but it is also the case that culture is a universal requirement for development. The interdependence of human communities—which probably had its origins in collaborative hunting and cooperative childrearing—seems to have placed demands on children’s development, selecting for a sensitivity to norms and to other people’s goals and intentions. Every child is born into a family and community with a language, customs, and conventions, and in which people have institutional rights and responsibilities. These define universal requisites of human psychological development: These include the acquisition of language, the development of a social identity, the understanding of community obligations, and the ability to contribute to the reproduction of the community. An open question today is the character of the capacities that children bring to these developmental tasks: the apparently species-unique ability that has made possible vast “cumulative” societies.
Dyslexia, or a reading disability, occurs when an individual has great difficulty at the level of word reading and decoding. Comprehension of text, writing, and spelling are also affected. The diagnosis of dyslexia involves the use of reading tests, but the continuum of reading performance means that any cutoff point is arbitrary. The IQ score does not play a role in the diagnosis of dyslexia. Dyslexia is a language-based learning disability. The cognitive difficulties of dyslexics include problems with recognizing and manipulating the basic sounds in a language, language memory, and learning the sounds of letters. Dyslexia is a neurological condition with a genetic basis. There are abnormalities in the brains of dyslexic individuals. There are also differences in the electrophysiological and structural characteristics of the brains of dyslexics. Hope for dyslexia involves early detection and intervention and evidence-based instruction.
Daniel L. Schacter, Aleea L. Devitt, and Donna Rose Addis
Episodic future thinking refers to the ability to imagine or simulate experiences that might occur in an individual’s personal future. It has been known for decades that cognitive aging is associated with declines in episodic memory, and recent research has documented correlated age-related declines in episodic future thinking. Previous research has considered both cognitive and neural mechanisms that are responsible for age-related changes in episodic future thinking, as well as effects of aging on the functions served by episodic future thinking. Studies concerned with mechanism indicate that multiple cognitive mechanisms contribute to changes in episodic future thinking during aging, including episodic memory retrieval, narrative style, and executive processes. Recent studies using an episodic specificity induction—brief training in recollecting episodic details of a recent experience—have proven useful in separating the contributions of episodic retrieval from other non-episodic processes during future thinking tasks in both old and young adults. Neuroimaging studies provide preliminary evidence of a role for age-related changes in default and executive brain networks in episodic future thinking and autobiographical planning. Studies concerned with function have examined age-related effects on the link between episodic future thinking and a variety of processes, including everyday problem-solving, prospective memory, prosocial intentions, and intertemporal choice/delay discounting. The general finding in these studies is for age-related reductions, consistent with the work on mechanisms that consistently reveals reduced episodic detail in older adults when they imagine future events. However, several studies have revealed that episodic simulation nonetheless confers some benefits for tasks tapping adaptive functions in older adults, such as problem-solving, prospective memory, and prosocial intentions, even though age-related deficits on these tasks are not eliminated or reduced by episodic future thinking.
Healthy and Pathological Neurocognitive Aging: Spectral and Functional Connectivity Analyses Using Magnetoencephalography
Gianluca Susi, Jaisalmer de Frutos-Lucas, Guiomar Niso, Su Miao Ye-Chen, Luis Antón Toro, Brenda Nadia Chino Vilca, and Fernando Maestú
Oscillatory activity present in brain signals reflects the underlying time-varying electrical discharges within and between ensembles of neurons. Among the variety of non-invasive techniques available for measuring of the brain’s oscillatory activity, magnetoencephalography (MEG) presents a remarkable combination of spatial and temporal resolution, and can be used in resting-state or task-based studies, depending on the goals of the experiment.
Two important kinds of analysis can be carried out with the MEG signal: spectral a. and functional connectivity (FC) a. While the former provides information on the distribution of the frequency content within distinct brain areas, FC tells us about the dependence or interaction between the signals stemming from two (or among many) different brain areas.
The large frequency range combined with the good resolution offered by MEG makes MEG-based spectral and FC analyses able to highlight distinct patterns of neurophysiological alterations during the aging process in both healthy and pathological conditions. Since disruption in spectral content and functional interactions between brain areas could be accounted for by early neuropathological changes, MEG could represent a useful tool to unveil neurobiological mechanisms related to the cognitive decline observed during aging, particularly suitable for the detection of functional alterations, and then for the discovery of potential biomarkers in case of pathology.
The aging process is characterized by alterations in the spectral content across the brain. At the network level, FC studies reveal that older adults experience a series of changes that make them more vulnerable to cognitive interferences.
While special attention has been dedicated to the study of pathological conditions (in particular, mild cognitive impairment and Alzheimer’s disease), the lack of studies addressing the features of FC in healthy aging is noteworthy. This area of research calls for future attention because it is able to set the baseline from which to draw comparisons with different pathological conditions.
Emma V. Ward and David R. Shanks
It is well documented that explicit (declarative, conscious) memory declines in normal aging. Studies have shown a progressive reduction in this form of memory with age, and healthy older adults (typically aged 65+ years) usually perform worse than younger adults (typically aged 18–30 years) on laboratory tests of explicit memory such as recall and recognition. In contrast, it is less clear whether implicit (procedural, unconscious) memory declines or remains stable in normal aging. Implicit memory is evident when previous experiences affect (e.g., facilitate) performance on tasks that do not require conscious recollection of those experiences. This can manifest in rehearsed motor skills, such as playing a musical instrument, but is typically indexed in the laboratory by the greater ease with which previously studied information is processed relative to non-studied information (e.g., repetition priming). While a vast amount of research has accumulated to suggest that implicit memory remains relatively stable over the adult lifespan, and is similar in samples of young and older adults, other studies have in contrast revealed that implicit memory is subject to age-related decline. Improving methods for determining whether implicit memory declines or remains stable with age is an important goal for future research, as the issue not only has significant implications for an aging society regarding interventions likely to ameliorate the effects of age-related explicit memory decline, but can also inform our theoretical understanding of human memory systems.
DeMond M. Grant and Evan J. White
Cognitive control is the ability to direct attention and cognitive resources toward achieving one’s goals. However, research indicates that anxiety biases multiple cognitive processes, including cognitive control. This occurs in part because anxiety leads to excessive processing of threatening stimuli at the expense of ongoing activities. This enhanced processing of threat interferes with several cognitive processes, which includes how individuals view and respond to their environment. Specifically, research indicates that anxious individuals devote their attention toward threat when considering both early, automatic processes and later, sustained attention. In addition, anxiety has negative effects on working memory, which involves the ability to hold and manipulate information in one’s consciousness. Anxiety has been found to decrease the resources necessary for effective working memory performance, as well as increase the likelihood of negative information entering working memory. Finally, anxiety is characterized by focusing excessive attention on mistakes, and there is also a reduction in the cognitive control resources necessary to correct behavior. Enhancing our knowledge of how anxiety affects cognitive control has broad implications for understanding the development of anxiety disorders, as well as emerging treatments for these conditions.
Sleep health is understood as a key factor in lifelong health and for social participation, function, and satisfaction. In later life, insomnia and other sleep disturbances are common. Insomnia is experienced as poor, disrupted, or insufficient sleep associated with significant daytime impairments including increased fatigue or reduced energy, impaired cognitive function, and increased mood disturbance. Poor sleep is associated with negative outcomes across a range of dimensions that impair quality of life, increases risk for other diseases, and may interact negatively with the progression and treatment of other disorders. Evidence for effective psychological interventions to improve sleep in later life, specifically cognitive behavioral therapy for insomnia, is robust and well described. Good sleep should be understood as a substrate for psychological health and a reasonable expectation in later life.
Erica H. Wojcik, Irene de la Cruz-Pavía, and Janet F. Werker
Language is a structured form of communication that is unique to humans. Within the first few years of life, typically developing children can understand and produce full sentences in their native language or languages. For centuries, philosophers, psychologists, and linguists have debated how we acquire language with such ease and speed. Central to this debate has been whether the learning process is driven by innate capacities or information in the environment. In the field of psychology, researchers have moved beyond this dichotomy to examine how perceptual and cognitive biases may guide input-driven learning and how these biases may change with experience. There is evidence that this integration permeates the learning and development of all aspects of language—from sounds (phonology), to the meanings of words (lexical-semantics), to the forms of words and the structure of sentences (morphosyntax). For example, in the area of phonology, newborns’ bias to attend to speech over other signals facilitates early learning of the prosodic and phonemic properties of their native language(s). In the area of lexical-semantics, infants’ bias to attend to novelty aids in mapping new words to their referents. In morphosyntax, infants’ sensitivity to vowels, repetition, and phrase edges guides statistical learning. In each of these areas, too, new biases come into play throughout development, as infants gain more knowledge about their native language(s).
Lori E. James and Sara Anne Goring
The questions of whether and why language processes change in healthy aging require complicated answers. Although comprehension appears to be more stable across adulthood than does production, there is evidence for age-related changes and also for constancy within both input and output components of language. Further, these changes can be considered at various levels of the language hierarchy, such as sensory input, words, sentences, and discourse. As concluded in several other comprehensive reviews, older adults’ language production ability declines much more noticeably than does their comprehension, presumably because comprehension is able to benefit from contextual processing in a way that production cannot. Specifically, lexical and orthographic retrieval become more difficult during normal aging, and these changes appear to represent the most noticeable age-related declines in language production. Some theories of age-related decline focus on global deterioration of cognitive function, whereas other theories predict changes in specific processes related to language function. Both types of theories have received empirical support as applied to language performance, although additional theoretical development is still needed to capture the patterns of effects. Further, in order to truly understand how cognitive aging impacts the ability to understand and produce language, it is necessary to examine how age-related shifts in goals, expertise, and compensatory strategies influence language processes. There are important implications of research on language and cognitive aging, in that language can play a role in physical health and psychological well-being. In summary, our review of the existing literature on language and cognitive aging supports previous claims that language ability is asymmetrically impacted by age, with smaller overall effects of aging on comprehension than production processes.