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.
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Article
Aging and Cognitive Skill Learning
Jack Kuhns and Dayna R. Touron
Article
Autism Spectrum Disorders in Later Life
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.
Article
Awareness of Aging Processes
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.
Article
Binocular Vision
Suzanne McKee and Preeti Verghese
This article describes human binocular vision. While it is focused primarily on human stereopsis, it also briefly tells about other binocular functions, including binocular summation, rivalry, and vergence, the eye movement that is driven by stereopsis. Stereopsis refers to the depth perception generated by small differences in the locations of visual features in the two retinal images; these differences in retinal location are called disparities. Disparities are detected by special binocularly driven cortical neurons whose properties are outlined here; the article also describes studies that have used fMRI imaging to show that many areas of human cortex respond to depth based on disparity. The development of stereopsis in human infants, as well as clinical abnormalities in stereopsis, is also documented.
Article
Cerebral Palsy From a Developmental Psychology Perspective
Karen Lidzba
Cerebral palsy (CP) is defined as non-progressive damage to the brain at or around birth, which leads to varying symptoms depending on the extent and location of damage. The leading symptom is sensory-motor impairment of varying expression, but additional perceptual, cognitive, and socio-emotional symptoms are common. CP can be divided into four types, with bilateral spastic being by far the most frequent, followed by the unilateral spastic, the dyskinetic, and the ataxic variants. The intellectual, linguistic, and cognitive profile of CP is extremely variant, but all qualities correlate more or less with CP type and motor impairment. Early diagnosis is important since early intervention may promote all developmental dimensions. Generally, individuals with unilateral spastic CP have the best (almost normal) intellectual, linguistic, and cognitive outcomes, while those with bilateral spastic CP fare the worst. Language perception is often an individual strength, while language expression, and particularly speech, may be heavily impaired. Attention and executive functions are often impaired as compared to typically developing controls, even in those children with normal intellectual functioning. The same holds true for visual perceptual functions, which are impaired in almost half of all children and adolescents with CP. The potential neuropsychological dysfunctions are a risk factor for arithmetic functions and literacy. Obstacles to participate in society are high for individuals with CP and heavily dependent on their motor, language, intellectual, and cognitive functions. However, quality of life is good for most children and adolescents, and they develop a sound self-concept. On the other side, bully experience is more common than amongst typically developing children and is associated with behavior problems and executive dysfunction. The development of children and adolescents with CP is determined by a complex interplay between physical, intellectual, and neuropsychological functions.
Article
Cognitive Reserve in the Aging Brain
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.
Article
Critical Role of Social–Cognitive Age Representations
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.
Article
Culture and Human Development
Martin J. Packer and Michael Cole
There is growing appreciation of the role of culture in children’s psychological development (also called human ontogenesis). However, there are several distinct approaches to research on this matter. Cross-cultural psychology explores the causal influence of culture on differences in children’s development, treated as dependent variables. Researchers interested in the role of cultural learning in human evolution view culture as beliefs and values that are transferred from the mind of one individual to that of another.
By contrast, “cultural psychology” views culture not as a cause, but a constituent of human psychological functioning. It invites us to pay attention to the fact that humans live in societies filled with material artifacts, tools, and signs that mediate human activity; that is to say, they provide the means with which people interact with the world around them and with one another. From this perspective, culture provides constituents that are essential to human development: it has a constitutive role in development.
Although there continues to be much debate over how to define culture, it is generally agreed that different human social groups have distinct cultures, and it is common to assume 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. Every child is born into a family and community with a language, customs, and conventions, and in which people occupy institutional roles with rights and responsibilities. These facts define universal requisites of human psychological development and 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. The interdependence of human communities—which probably had its origins in collaborative foraging and cooperative childrearing—seems to have placed species-specific demands on children’s development, selecting for the capacity to acquire a sensitivity not only to people’s goals and intentions but also to rights and responsibilities.
Article
Culture, Language, and Thought
Mutsumi Imai, Junko Kanero, and Takahiko Masuda
The relations among language, culture, and thought are complex. The empirical evidence from diverse domains suggests that culture affects language, language affects thought, and universally shared perception and cognition constrain the structure of language. Although neither language nor culture determines thought, both seem to highlight certain aspects of the world, with stronger influence when there are no clear perceptible categories. Research must delve into how language, culture, perception, and cognition interact with one another across different domains.
Article
Development of Visually Guided Action
Peter Vishton
Humans use visual information to select, plan, and control nearly all actions that they perform. Children are born with the ability to perform some actions, while others emerge only after several months. For instance, newborn infants can direct their eyes to attractive stimuli, but they are unable to smoothly follow these stimuli if they move. Many factors influence the action abilities of children and adults. As children mature, they become stronger and able to more precisely control their bodies. The interactions that the children have with their environment matter a great deal as well, such that the age at which children gain particular action abilities varies widely. Some developmental changes are highly action- and context-specific, but other changes broadly influence cognitive development. For instance, learning to walk enhances children’s language development. An understanding of visually guided action development is thus essential to any complete theory of human mental development. Characterizing the development of visually guided action abilities provides a better understanding of mental and physical development as well as enabling insights into how visually guided actions are learned and controlled in adults.
Article
Dyslexia
Linda Siegel
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.
Article
Effects of Early Visual Deprivation
Brigitte Röder and Ramesh Kekunnaya
As a consequence of congenital blindness, compensatory performance in the intact sensory modalities has been documented in humans in many domains, including auditory and tactile perception, auditory localization, voice and language processing, and memory. Both changes of the neural circuits associated with the intact sensory systems (intramodal plasticity) and an activation of deprived visual cortex (crossmodal plasticity) have been observed in blind humans. Compensation in congenitally blind and late-blind individuals involves partially different neural mechanisms. If sight is restored in patients who were born with dense bilateral cataracts (opaque lenses preventing patterned light to reach the retina), considerable visual recovery has been observed in basic visual functions even after long periods of visual deprivation. Functional recovery has been found to be lower for higher-order visual processes, which has been linked to deficits in the functional specialization of neural circuits. First evidence has suggested that crossmodal plasticity largely retracts after sight restoration but that crossmodal activity does not seem to fully dissolve. In contrast, intramodal adaptations in the auditory system have been observed to persist after sight restoration. Except for predominantly subcortically mediated multisensory functions, many multisensory processes have been found to be altered even many years after sight restoration.
On the one hand, research in permanently blind humans has documented a high capability of the human neurocognitive system to adapt to an atypical environment. On the other hand, research in sight recovery individuals who had suffered a transient phase of visual deprivation following birth has demonstrated functional specific sensitive periods in the development of visual and multisensory neural circuits.
Article
Historical Psychology
Noemi Pizarroso Lopez
Historical psychology claims that the mind has a history, that is, that our ways of thinking, reasoning, perceiving, feeling, and acting are not necessarily universal or invariable, but are instead subject to modifications over time and space. The theoretical and methodological foundations of this movement were laid in France by psychologist Ignace Meyerson in his book Les fonctions psychologiques et les œuvres, published in 1948. His program stressed the active, experimental, constructive nature of human behavior, spanning behavioral registers as diverse as the linguistic, the religious, the juridical, the scientific/technical, and the artistic. All these behaviors involve aspects of different mental functions that we can infer through a proper analysis of “works,” considered as consolidated testimonies of human activity. As humanity’s successive achievements, constructed over the length of all the paths of the human experience, they are the materials with which psychology has to deal.
Meyerson refused to propose an inventory of functions to study. As unstable and imperfect products of a complex and uncertain undertaking, they can be analyzed only by avoiding the counterproductive prejudice of metaphysical fixism. Meyerson spoke in these terms of both deep transformations of feelings, of the person, or of the will, and of the so-called “basic functions,” such as perception and the imaginative function, including memory, time, space, and object.
Before Meyerson the term “historical psychology” had already been used by historians like Henri Berr and Lucien Febvre, a founding member of the Annales school, who firmly envisioned a sort of collective psychology of times past. Meyerson and his disciples eventually vied with their fellow historians of the Annales school for the label of “historical psychology” and criticized their notions of mentality and outillage mental. The Annales historians gradually abandoned the label, although they continued to cultivate the idea that mental operations and emotions have a history through the new labels of a “history of mentalities” and, more recently at the turn of the century, a “history of emotions.” While Meyerson and a few other psychologists kept using the “historical psychology” label, however, mainstream psychology remained quite oblivious to this historical focus. The greatest efforts made today among psychologists to think of our mental architecture in terms of transformation over time and space are probably to be found in the work of Kurt Danziger and Roger Smith.
Article
Language Acquisition
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).
Article
Language and Cognitive Aging
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.
Article
Life Space in Older Adults
Markus Wettstein, Hans-Werner Wahl, and Michael Schwenk
When referring to life space, researchers usually mean the area in which individuals move in their everyday lives. Life space can be measured based on different approaches, by means of self-reports (i.e., questionnaires or diaries) or by more recent approaches of technology-based objective assessment (e.g., via Global Positioning System [GPS] devices or smartphones). Life space is an important indicator of older adults’ out-of-home mobility and is meaningfully associated with autonomy, well-being, and quality of life. Substantial relationships between life space and socio-demographic indicators, health, and cognitive abilities have been reported in previous research. Future research on life space in old age will benefit from a more comprehensive and stronger interdisciplinary perspective, from taking into account different time scales (i.e., short- and long-term variability), and from considering life space as a multidimensional measure that can be best assessed based on multi-method approaches with multiple indicators.
Article
Longitudinal, Cross-Sectional, and Sequential Designs in Lifespan Developmental Psychology
Susan Krauss Whitbourne
Research methods in lifespan development include single-factor designs that either follow a single cohort of individuals over time or compare age groups at a single time point. The two basic types of studies involving the manipulation of the single factors of age, cohort, and time of measurement are longitudinal and cross-sectional. Each of these has advantages and disadvantages, but both are characterized by limitations because they cannot definitively separate the joint influences of age, cohort, and type of measurement. The third group of designs involves manipulation of two or more levels of each factor to permit inferences to be drawn that separate personal from social aging.
The theoretical problems involved in both the single-factor and sequential designs combine with practical issues to present lifespan developmental researchers with a number of choices in approaching the variables of interest. The theoretical problems include the inevitable linking of personal with social aging, particularly evident in single-factor designs, and the fact that selective attrition leads to the differential availability of increasingly select older samples. Practical problems include the need to assign participants to appropriate age intervals and such clerical issues as the need to track participants in follow-up investigations. Researchers must also be aware of methodological issues related to task equivalence across individuals of different ages and the need to covary for potential confounds that could lead to differences across groups of participants due to such factors as education and health status.
The increasing recognition of the need to address these issues is leading to a body of literature that reflects the growing sophistication of the field along with the more widespread availability of sophisticated analytic methods. As these improvements continue to raise the level of scholarship in the field, there will be a greater understanding of both ontogenetic change as well as the influence of context on development from childhood through later life.
Article
Metamemory and Cognitive Aging
Christopher Hertzog and Taylor Curley
Metamemory is defined as cognitions about memory and related processes. Related terms in the literature include metacognition, self-evaluation, memory self-efficacy, executive function, self-regulation, cognitive control, and strategic behavior. Metamemory is a multidimensional construct that includes knowledge about how memory works, beliefs about memory (including beliefs about one’s own memory such as memory self-efficacy), monitoring of memory and related processes and products, and metacognitive control, in which adaptive changes in processing approaches and strategies may be contemplated if monitoring of memory processes (encoding, retention, retrieval) indicates that alternative strategies may be required. Older adults generally believe that their memory has declined and that, on average, they have less control over memory and lower memory self-efficacy than young and middle-aged adults. Many but not all aspects of online memory monitoring are well preserved in old age, such as the ability to discriminate between information that has been learned versus not learned. A major exception concerns confidence judgments concerning whether recognition memory decisions are correct; older adults are more prone to high-confidence memory errors, believing they are recognizing something they have not encountered previously. The evidence regarding metacognitive control is more mixed, with some hints that older adults do not use monitoring to adjust control behaviors (e.g., devoting more time and effort to studying items they believe have not yet been well-learned). However, any age deficits in self-regulation based on memory monitoring or adaptive strategy use can probably be addressed through instructions, practice, or training. In general, older adults seem capable of exerting metacognitive control in memory studies, although they may not necessarily do so without explicit support or prompting.
Article
Motor Development: Biological Aspects of Brain and Behavior
Audrey van der Meer and F. R. (Ruud) van der Weel
Developmental psychology has a long history of linking motor development to enhancement in perceptual and cognitive abilities. Because of the haphazard appearance of the very first movements, the human infant is often thought to be born with an immature brain. However, behavioral and brain research shows that infants have advanced brains that are ready to learn even before birth. The infant brain doubles in both size and weight during the first year of life. During infancy, nerve cells increase dramatically in number, they become more specialized, and up to a thousand new connections per second are formed between them. The foundation for the brain’s infrastructure is formed during the first thousand days of life. Different neural networks are formed in response to the quantity and quality of experiences a child is exposed to. In addition, the growing brain is open and moldable, it can adapt to the changing conditions surrounding it, and the brains of infants and small children show the most plasticity. Developmental neuroscience research suggests that as soon as babies start crawling at around 9 months of age, they undergo remarkable development of prospective control and timing skills at both the brain and behavioral levels when dealing with visual motion. Only a few weeks after crawling onset, infants process visual motion faster and more efficiently, and they differentiate between motion speeds and directions. Stimulating the development of motor skills that allow babies to start exploring their surroundings by themselves earlier is therefore likely to facilitate brain development.
Article
Music Perception
Marcus T. Pearce
Music perception covers all aspects of psychological and neural processing invoked while listening to music. In order to make sense of a musical stimulus, the perceptual system must infer an internal representation of the structure present in a piece of music, including the attributes of individual events (including pitch, timbre, loudness, and timing), groups of events (such as chords, voices, and phrases), and structural relationships between such groups, so that larger-scale aspects of musical form and thematic structure can be perceived. Such representations are stored in memory at timescales ranging from seconds for echoic memory to decades in the case of long-term memory for music, which consists of schematic knowledge of musical styles, veridical memory for particular familiar pieces of music, and episodic memory for music heard at a particular place and time. Stored representations of music allow the generation of top-down expectations for the attributes of forthcoming events while listening to music, which play a role in the perception of music as it unfolds dynamically in time and also the emotional and aesthetic experience of music. Music is a communicative medium conveying affective meaning from the composer and performer to the listener, via several psychological mechanisms and using a range of cues in the music, some of which are universal, others culture-specific. Individuals show behavioral and physiological effects of listening to music from birth onward and learn the syntactic structure of the musical styles to which they are exposed within their culture, shaping their music perception. Some individuals undertake explicit musical training, which can additionally shape their perception of music, sometimes in fundamental ways. Listening to music can impair performance on concurrent tasks involving working memory due to competing access for resources but can improve performance when listening takes place prior to the task due to its positive effect on affective state. Music is a universal human cultural phenomenon whose complexity requires the activation of a diverse range of perceptual and cognitive mechanisms, making it an interesting target for psychological and neuroscientific investigation.
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