The basic premise of applied psychology is the use of psychological principles and theories to overcome problems in real life situations. Many areas of our lives and society have been influenced and changed by the often unnoticed application of psychological principles. Mental health,organizational psychology business management, education, health, product design, ergonomics, and law are just a few of the areas that have been influenced by the application of psychological principles and findings. The umbrella of applied psychology includes the areas of clinical psychology, counseling psychology, industrial and organizational psychology, occupational health psychology, human factors, forensic psychology, engineering psychology, as well as many other areas such as school psychology, sports psychology and community psychology. In addition, a number of specialized areas in the general field of psychology have applied branches (e.g., applied social psychology, applied cognitive psychology). However, the lines between sub-branch specializations and major applied psychology categories are often blurred. For example, a human factors psychologist might use a cognitive psychology theory. Is this human factor psychology or applied cognitive psychology?
So what sets applied psychology apart from other categories of psychology? An example helps to best explain this. Lets say there is a small team of cognitive psychologists researching attention span. They like many researchers are at a university using 18 year old undergrads as participants in the lab located next door to their office. They collect statistically significant data and develop a model for how to suddenly grab a person's attention. An applied psychologist will take this concept and see how this newly developed model implements in their particular sub-field. A human factors psychologist might use the cognitive psychologists finding to develop a system that gets drivers attention enabling the driver to avoid car wrecks. An environmental psychologist might use the same laboratory findings to attract students attention to a particular area of the classroom thus increasing learning. Applied psychology is being implemented into peoples everyday lives, and improving their lives, though it is rarely noticed or being credited as an application of psychology.
History of Applied Psychology 
One founder of applied psychology was Hugo Münsterberg. He came to America from Germany, and, like many aspiring psychologists during the late 19th century, originally studied philosophy. Münsterberg had many interests in the field of psychology such as purposive psychology, social psychology and forensic psychology. In 1907 he wrote several magazine articles concerning legal aspects of testimony, confessions and courtroom procedures, which eventually developed into his book, On the Witness Stand. The following year the Division of Applied Psychology was adjoined to the Harvard Psychological Laboratory. Within 9 years he had contributed eight books in English, applying psychology to education, industrial efficiency, business and teaching. Eventually Hugo Münsterberg and his contributions would define him as the creator of applied psychology. In 1920, the International Association of Applied Psychology (IAAP) was founded, as the first international scholarly society within the field of psychology.
Clinical psychology 
Clinical psychology includes the study and application of psychology for the purpose of understanding, preventing, and relieving psychologically-based distress or dysfunction and to promote subjective well-being and personal development. Central to its practice are psychological assessment and psychotherapy, although clinical psychologists may also engage in research, teaching, consultation, forensic testimony, and program development and administration. Some clinical psychologists may focus on the clinical management of patients with brain injury—this area is known as clinical neuropsychology. In many countries clinical psychology is a regulated mental health profession.
The work performed by clinical psychologists tends to be done inside various therapy models, all of which involve a formal relationship between professional and client—usually an individual, couple, family, or small group—that employs a set of procedures intended to form a therapeutic alliance, explore the nature of psychological problems, and encourage new ways of thinking, feeling, or behaving. The four major perspectives are psychodynamic, cognitive behavioral, existential-humanistic, and systems or family therapy. There has been a growing movement to integrate these various therapeutic approaches, especially with an increased understanding of issues regarding ethnicity, gender, spirituality, and sexual-orientation. With the advent of more robust research findings regarding psychotherapy, there is growing evidence that most of the major therapies are about of equal effectiveness, with the key common element being a strong therapeutic alliance. Because of this, more training programs and psychologists are now adopting an eclectic therapeutic orientation.
Clinical psychologists do not usually prescribe medication, although there is a growing number of psychologists who do have prescribing privileges, in the field of medical psychology. In general, however, when medication is warranted many psychologists will work in cooperation with psychiatrists so that clients get all their therapeutic needs met. Clinical psychologists may also work as part of a team with other professionals, such as social workers and nutritionists.
Educational psychology 
Educational psychology is devoted to the study of how humans learn in educational settings, especially schools, and the effectiveness of educational interventions (e.g., phonics versus whole language instruction in early reading attainment). Another domain of educational psychology is the psychology of teaching. In some colleges, educational psychology courses are called "the psychology of learning and teaching". Educational psychology derives a great deal from basic-science disciplines within psychology including cognitive science and behaviorially-oriented research on learning.
Forensic psychology and legal psychology 
Forensic psychology and legal psychology are the area concerned with the application of psychological methods and principles to legal questions and issues. Most typically, forensic psychology involves a clinical analysis of a particular individual and an assessment of some specific psycho-legal question. The psycho-legal question does not have to criminal in nature. In fact, the forensic psychologist rarely gets involved in the actual criminal investigations. Custody cases are a great example of non-criminal evaluations by forensic psychologists. The validity and upholding of eyewitness testimony is an area of forensic psychology that does veer closer to criminal investigations, though does not directly involve the psychologist in the investigation process. Legal psychology refers to any application of psychological principles, methods or understanding to legal questions or issues. In addition to the applied practices, legal psychology also includes academic or empirical research on topics involving the relationship of law to human mental processes and behavior. It is interesting to note the inherent differences that arise when placing psychology in the legal context. Psychology rarely makes absolute statements. Instead, psychologists traffic in the terms like level of confidence, percentages, and significance. Legal matters, on the other hand, look for absolutes: guilty or not guilty. This makes for a sticky union between psychology and the legal system.
Health psychology 
Health psychology concerns itself with understanding how biology, behavior, and social context influence health and illness. Health psychologists generally work alongside other medical professionals in clinical settings, although many also teach and conduct research. Although its early beginnings can be traced to the kindred field of clinical psychology, four different approaches to health psychology have been defined: clinical, public health, community and critical health psychology. Health psychologists also aim to change health behaviors for the dual purpose of helping people stay healthy and helping patients adhere to disease treatment regimens. The medical view on these issues differs from the health psychology views in that the health psychologists view the person's mental condition as heavily related to their physical condition and must be examined and treated in unison. The medical view, on the other hand, tends to look mainly at treating the physical condition or ailment. The focus of health psychologists tend to center around the health crisis facing the western world particularly in the US. Cognitive behavioral therapy and behavior modification are techniques often employed by health psychologists.
Human factors 
Human factors is the study of how cognitive and psychological processes affect our interaction with tools, machines, and objects in the environment. Many branches of psychology attempt to create models of and understand human behavior. These models are usually based on data collected from experiments. Human Factor psychologists however, take the same data and use it to design or adapt processes and objects that will compliment the human component of the equation. Rather than humans learning how to use and manipulate a piece of technology, human factors strives to design technology to be inline with the human behavior models designed by general psychology. This could be accounting for physical limitations of humans, as in ergonomics, or designing systems, especially computer systems, that work intuitively with humans, as does engineering psychology.
Ergonomics is applied primarily through office work and the transportation industry. Psychologists here take into account the physical limitations of the human body and attempt to reduce fatigue and stress by designing products and systems that work within the natural limitations of the human body. From simple things like the size of buttons and design of office chairs to layout of airplane cockpits, human factor psychologists, specializing in ergonomics, attempt to de-stress our everyday lives and sometimes even save them.
Human factor psychologists specializing in engineering psychology tend to take on slightly different projects than their ergonomic centered counterparts. These psychologists look at how a human and a process interact. Often engineering psychology may be centered around computers. However at the base level, a process is simply a series of inputs and outputs between a human and a machine. The human must have a clear method to input data and be able to easily access the outputted information. The inability of rapid and accurate corrections can sometimes lead to drastic consequences, as summed up by many stories in Set Phases on Stun. The engineering psychologists wants to make the process of inputs and outputs as intuitive as possible for the user.
The goal of research in human factors is to understand the limitations and biases of human mental processes and behavior, and design items and systems that will interact accordingly with the limitations. Some may see human factors as intuitive or a list of dos and don'ts, but in reality, human factor research strives to find the make sense of large piles of data to bring precise applications to [product designs and systems to help people work more naturally, intuitively with the items of their surroundings.
Industrial and organizational psychology 
Industrial and organizational psychology, commonly referred to as I/O psychology, focuses to varying degrees on the psychology of the workforce, customer, and consumer, including issues such as the psychology of recruitment, selecting employees from an applicant pool which overall includes training, performance appraisal, job satisfaction, work behavior, stress at work and management. In short, I/O psychology is the application of psychology to the workplace.
Though the name of the title "Industrial Organizational Psychology" implies 2 split disciplines being chained together, it is near impossible to have one half without the other. If asked to generally define the differences, Industrial psychology focuses more on the Human Resources aspects of the field, and Organizational psychology focuses more on the personal interactions of the employees. When applying these principles however, they are not easily broken apart. For example, when developing requirements for a new job position, the recruiters are looking for an applicant with strong communication skills in multiple areas. The developing of the position requirements falls under the industrial psychology, human resource type work. and the requirement of communication skills is related to how the employee with interacts with co-workers. As seen here, it is hard to separate task of developing a qualifications list from the types of qualifications on the list. This is parallel to how the I and O are nearly inseparable in practice. Therefore, I/O psychologists are generally rounded in both industrial and organizational psychology though they will have some specialization. Other topics of interest for I/O psychologists include performance evaluation, training, and much more.
Occupational health psychology 
Occupational health psychology (OHP) is a relatively new discipline that emerged out of the confluence of health psychology, industrial and organizational psychology, and occupational health. OHP has its own doctoral programs, journals, and professional organizations. The field is concerned with identifying psychosocial characteristics of workplaces that give rise to health-related problems in people who work. These problems can involve physical health (e.g., cardiovascular disease) or mental health (e.g., depression). Examples of psychosocial characteristics of workplaces that OHP has investigated include amount of decision latitude a worker can exercise and the supportiveness of supervisors. OHP is also concerned with the development and implementation of interventions that can prevent or ameliorate work-related health problems. In addition, OHP research has important implications for the economic success of organizations. Other research areas of concern to OHP include workplace incivility and violence, work-home carryover, unemployment and downsizing, and workplace safety and accident prevention. Two important OHP journals are the Journal of Occupational Health Psychology and Work & Stress. Two important organizations closely associated with OHP are the Society for Occupational Health Psychology and the European Academy of Occupational Health Psychology.
School psychology 
School psychology is a field that applies principles of clinical psychology and educational psychology to the diagnosis and treatment of students' behavioral and learning problems. School psychologists are educated in child and adolescent development, learning theories, psychological and psychoeducational assessment, personality theories, therapeutic interventions, special education, psychology, consultation, child and adolescent psychopathology, and the ethical, legal and administrative codes of their profession.
According to Division 16 (Division of School Psychology) of the American Psychological Association (APA), school psychologists operate according to a scientific framework. They work to promote effectiveness and efficiency in the field. School psychologists conduct psychological assessments, provide brief interventions, and develop or help develop prevention programs. Additionally, they evaluate services with special focus on developmental processes of children within the school system, and other systems, such as families. School psychologists consult with teachers, parents, and school personnel about learning, behavioral, social, and emotional problems. They may teach lessons on parenting skills (like school counselors), learning strategies, and other skills related to school mental health. In addition, they explain test results to parents and students. They provide individual, group, and in some cases family counseling (State Board of Education 2003; National Clearinghouse for Professions in Special Education, n.d.). School psychologists are actively involved in district and school crisis intervention teams. They also supervise graduate students in school psychology. School psychologists in many districts provide professional development to teachers and other school personnel on topics such as positive behavior intervention plans and achievement tests.
School psychologists are influential within the school system and are frequently consulted to solve problems. Practitioners should be able to provide consultation and collaborate with other members of the educational community and confidently make decisions based on empirical research.
Sport psychology is a specialization within psychology that seeks to understand psychological/mental factors that affect performance in sports, physical activity and exercise and apply these to enhance individual and team performance. The sport psychology approach differs from the coaches and players perspective. Coaches tend to narrow their focus and energy towards the end-goal. They are concerned with the actions that lead to the win, as opposed to the sport psychologist who tries to focus the players thoughts on just achieving the win. Sport psychology trains players mentally to prepare them, whereas coaches tend to focus mostly on physical training. Sport psychology deals with increasing performance by managing emotions and minimizing the psychological effects of injury and poor performance. Some of the most important skills taught are goal setting, relaxation, visualization, self-talk awareness and control, concentration, using rituals, attribution training, and periodization. The principles and theories may be applied to any human movement or performance tasks (e.g., playing a musical instrument, acting in a play, public speaking, motor skills). Usually, experts recommend that students be trained in both kinesiology (i.e., sport and exercise sciences, physical education) and counseling.
Environmental Psychology 
Environmental psychology is the psychological study of humans and their interactions with their environments. The types of environments studied are limitless, ranging from homes, offices, classrooms, factories, nature, and so on. However, across these different environments, there are several common themes of study that emerge within each one. Noise level and ambient temperature are clearly present in all environments and often subjects of discussion for environmental psychologists. Crowding and stressors are a few other aspects of environments studied by this sub-discipline of psychology. When examining a particular environment, environmental psychology looks at the goals and purposes of the people in the using the environment, and tries to determine how well the environment is suiting the needs of the people using it. For example, a quiet environment is necessary for a classroom of students taking a test, but would not be needed or expected on a farm full of animals. The concepts and trends learned through environmental psychology can be used when setting up or rearranging spaces so that the space will best perform its intended function. The top common, more well known areas of psychology that drive this applied field include: cognitive, perception, learning, and social psychology.
Additional areas 
- Community psychology
- Counseling psychology
- Ecological psychology
- Media psychology
- Military psychology
- Operational psychology
- Traffic psychology
See also 
- List of important publications in psychology
- Social work
- Outline of psychology
- American Psychological Association, Division 12, "About Clinical Psychology"
- Brain, Christine. (2002). Advanced psychology: applications, issues and perspectives. Cheltenham: Nelson Thornes. ISBN 0-17-490058-9>
- Leichsenring, Falk & Leibing, Eric. (2003). The effectiveness of psychodynamic therapy and cognitive behavior therapy in the treatment of personality disorders: A meta-analysis. The American Journal of Psychiatry, 160(7), 1223–1233.
- Reisner, Andrew. (2005). The common factors, empirically validated treatments, and recovery models of therapeutic change. The Psychological Record, 55(3), 377–400.
- Klusman, Lawrence. (2001). Prescribing Psychologists and Patients' Medical Needs; Lessons From Clinical Psychiatry. Professional Psychology: Research and Practice, 32(5), 496.
- Huss, M. T. What is forensic psychology? It's not Silence of the Lambs! Eye on Psi Chi vol. 5 (2001). pp. 25–27
- Custody evaluation practices: A survey of experienced professionals (revisited). Ackerman, Marc J.; Ackerman, Melissa C. Professional Psychology: Research and Practice, Vol 28(2), Apr 1997, 137-145. doi: 10.1037/0735-7028.28.2.137
- Ogloff, J. R., and Finkelman, D. (1999). Psychology and law: An overview. In R. Roesch, ed. , S. D. Hart, ed. , & J. R. P. Ogloff (Eds.), Psychology and law: The state of the discipline (pp. 1–20). New York: Kluwer Academic/Plenum.
- APA, Division 38. What a Health Psychologist Does and How to Become One. Retrieved 03-04-2007.
- Marks, D.F., Murray, M. et al. (2005). "Health Psychology: Theory, Research & Practice." London, England: Sage Publications. ISBN 1-4129-0336-X
- Friedman, H. S., ed. , & Silver, R. C. (Eds.). (2007). Foundations of health psychology. New York: Oxford University Press.
- Meister, D. (1999). The history of human factors and ergonomics. Mahwah, NJ: Erlbaum.
- Roscoe, S. N. (1997). The adolescence of engineering psychology. In S. M. Casey (Series Ed.), Human factors history monograph series (Vol. 1). Santa Monica, CA: Human Factors and Ergonomics Society.
- Everly, G.S., Jr. (1986). An introduction to occupational health psychology. In P.A. Keller & L.G. Ritt (Eds.), Innovations in clinical practice: A source book, Vol. 5 (pp. 331–338). Sarasota, FL: Professional Resource Exchange.
- Bosma, H., Marmot, M.G., Hemingway, H., Nicholson, A.C., Brunner, E., & Stansfeld, S.A. (1997). Low job control and risk of coronary heart disease in Whitehall II (prospective cohort) study. British Medical Journal, 314, 558–565.
- Tucker, J.S., Sinclair, R.R., & Thomas, J.L. (2005). The multilevel effects of occupational stressors on soldiers' well-being: Organizational attachment, and readiness. Journal of Occupational Health Psychology, 10, 276–299.
- Karasek, R.A. (1979). Job demands, job decision latitude, and mental strain: Implications for job redesign. Administrative Science Quarterly, 24, 285–307.
- Moyle, P. (1998). Longitudinal influences of managerial support on employee well-being. Work & Stress, 12, 29–49
- Schmitt, L. (2007). OHP interventions: Wellness programs. Newsletter of the Society for Occupational Health Psychology, 1, 4–5. 
- Adkins, J.A. (1999). Promoting organizational health: The evolving practice of occupational health psychology. Professional Psychology: Research and Practice, 30, 129–137.
- Cortina, L.M., Magley, V.J., Williams, J.H., & Langhout, R.D. (2001). Incivility in the workplace: Incidence and impact. Journal of Occupational Health Psychology, 6, 64–80.
- Kelloway, E.K., Barling, J., & Hurrell, J.J. (Eds). Handbook of workplace violence. Thousand Oaks, CA: Sage Publications.
- Haines, V.Y. III, Marchand, A., & Harvey, S. (2006). Crossover of workplace aggression experiences in dual-earner couples. Journal of Occupational Health Psychology, 11, 305–314.
- Feldt, T., Leskinen, E., & Kinnunen, U. (2005). Structural invariance and stability of sense of coherence: A longitudinal analysis of two groups with different employment experiences. Work & Stress, 19, 68–83.
- Moore, S., Grunberg, L., & Greenberg, E. (2004). Repeated downsizing contact: The effects of similar and dissimilar layoff experiences on work and well-being outcomes. Journal of Occupational Health Psychology, 9, 247–257.
- Kidd, P., Scharf, T., & Veazie, M. (1996) Linking stress and injury in the farming environment: A secondary analysis. Health Education Quarterly, 23, 224–237.
- Williamson, A.M., & Feyer, A.-M.(1995). Causes of accidents and the time of day. Work & Stress, 9, 158–164.
- Ravizza, K. (2006). Increasing awareness for sport performance. In J. M. Williams (Ed.), Applied sport psychology (pp. 228–239). New York: McGraw-Hill.
- Anderson, C. A. Temperature and aggression: Ubiquitous effects of heat on occurrence of human violence. Psychological Bulletin vol. 106 (1989). pp. 74–96 http://dx.doi.org.libproxy.clemson.edu/10.1037/0033-2909.106.1.74
- Ravizza, K. (2006). Increasing awareness for sport performance. In J. M. Williams (Ed.), Applied sport psychology (pp. 228–239). New York: McGraw-Hill.
- Weinstein, C. S. The physical environment of the school: A review of the research. Review of Educational Research vol. 49 (1979). pp. 577–610