Occupational science is a discipline in the social and behavioral sciences dedicated to the study of humans as "doers" or "occupational beings". As used here, the term "occupation" refers to the goal-directed activities that characterize daily human life as well as the characteristics and patterns of purposeful activity that occur over lifetimes as these affect health and well-being.
Occupational science evolved as a loosely organized effort by many scholars in different disciplines to understand human time use. It was named and given additional impetus in 1989 by a team of faculty at the University of Southern California (USC) led by Elizabeth Yerxa, who had been influenced by the work of graduate students under the supervision of Mary Reilly at the same university.  Since its formal beginning at that time, which coincided with the establishment of a Ph.D.program in Occupational Science at USC; occupational science has evolved as an important way to expand empirical knowledge underlying the profession of occupational therapy.
Link between occupational science and occupational therapy
Occupational science was developed by occupational therapists who drew from original ideas predating the founding of occupational therapy. It is thus considered to be a developing or emerging academic discipline. The substrates (or underlying dimensions) of occupation (form, function, and meaning) are difficult to observe and quantify, and thus require and benefit from a multidisciplinary approach. While both occupational science and occupational therapy are rooted in systems theory and compatible with a holistic approach, the methods for observing and understanding an occupation's form (how something is done), function (its purpose), and meaning (how it is understood by the doer) are not always holistic in approach. For instance, disciplines such as biomechanics and psychology inform occupational science but, individually, are not necessarily concerned about how their explanations contribute to an integrated understanding of the factors influencing of a person's daily life . Clinical practice in occupational therapy can prompt new ideas and spark potential research within the discipline of occupational science; although typically, knowledge from academic disciplines precedes the application of such knowledge in applied fields.  Occupational science has the capacity to provide insight into the primary modality of occupational therapy (occupation) through studying the consequences of participation in occupation and its therapeutic benefits. 
Beyond the well-documented benefits of regular physical activity, occupations that engender purpose, competence and self esteem may provide psychological benefits related to satisfying needs for meaning . Life conditions that limit or restrict participation in meaningful occupations (such as refugeeism or incarceration) or lead to participation in harmful occupations, (such as substance abuse or risky behaviors), can lead to “illness, isolation and despair,” or even death. However, participation in occupations shown to be beneficial or restorative can enhance health. Through participation in engaging or restorative occupations, the mental state of individuals can be improved and result in feelings of regeneration. Sleep, an area of occupation, not only regenerates physical and cognitive processes, but also is required for satisfactory occupational functioning. Participating in other relaxing or tension-reducing occupations, such as reading a book, going for a walk, or exercising, may provide physical, cognitive, and mental restoration and stress reduction.
Empirical research linking the perceived psychological and physiological benefits of participation in different types of daily human occupation is ongoing. Questions about the nature of different dimensions of human occupation and their influences on human identity, behavior and states of being are viewed by occupational scientists as suitable areas of investigation. Developmental theorists have long hypothesized that the occupations of childhood and activity related events characteristic of different stages of adulthood are critical factors in physical, cognitive and psychological growth and maturation .
Similarly, there is ongoing interest in how patterns of daily time use, including habits, routines, and lifestyles, may be related to states of well being . Adolf Meyer, a prominent early psychiatrist and advocate for occupational therapy in the United States, was among the first to speculate that a regular pattern, rhythm or flow of daily occupations contributed to mental health .
The development of occupational science as an academic discipline has been advanced through the creation of several university-based programs of study leading to undergraduate and graduate degrees in the field. Disciplines within which occupational scientists can be found include architecture, engineering, education, marketing, psychology, sociology, anthropology, economics, occupational therapy, public health, and geography. There are several national, regional and international societies dedicated to promoting the evolution of this specialized area of human science. Academic journals containing content directly relevant to occupational science include the Journal of Occupational Science OTJR: Occupation, Participation and Health,Journal of Happiness Studies, 'Quality of Life Research Applied Research in Quality of Life,Canadian Journal of Occupational Therapy,The Scandinavian Journal of Occupational Therapy, and various other occupational therapy journals.
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