Applied psychology

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Applied_psychology

 

Applied psychology is the use of psychological methods and findings of scientific psychology to solve practical problems of human and animal behavior and experience. Educational and organizational psychology, business management, law, health, product design, ergonomics, behavioural psychology, psychology of motivation, psychoanalysis, neuropsychology, psychiatry and mental health are just a few of the areas that have been influenced by the application of psychological principles and scientific findings. Some of the areas of applied psychology include counseling psychology, industrial and organizational psychology, engineering psychology, occupational health psychology, legal psychology, school psychology, sports psychology, community psychology, neuropsychology, medical psychology and clinical psychology, evolutionary psychology, human factors, forensic psychology and traffic psychology. In addition, a number of specialized areas in the general area 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 mixed or in some cases blurred. For example, a human factors psychologist might use a cognitive psychology theory. This could be described as human factor psychology or as applied cognitive psychology. When applied psychology is used in the treatment of behavioral disorders there are many experimental approaches to try and treat an individual. This type of psychology can be found in many of the subbranches in other fields of psychology.

History

Photo of Hugo Münsterberg

The founder of applied psychology was Hugo Münsterberg. He came to America (Harvard) from Germany (Berlin, Laboratory of Stern), invited by William James, 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. Hugo Münsterberg is credited with being one of the first people who has researched the field of applied psychology. He went to the University of Leipzig in Germany and attained his doctorate in Medicine. He opened the second psychology clinic in Germany in 1891 where he has continued his research. 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.

Most professional psychologists in the U.S. worked in an academic setting until World War II. But during the war, the armed forces and the Office of Strategic Services hired psychologists in droves to work on issues such as troop morale and propaganda design. After the war, psychologists found an expanding range of jobs outside of the academy. Since 1970, the number of college graduates with degrees in psychology has more than doubled, from 33,679 to 76,671 in 2002. The annual numbers of masters' and PhD degrees have also increased dramatically over the same period. All the while, degrees in the related fields of economics, sociology, and political science have remained constant.

Professional organizations have organized special events and meetings to promote the idea of applied psychology. In 1990, the American Psychological Society held a Behavioral Science Summit and formed the "Human Capital Initiative", spanning schools, workplace productivity, drugs, violence, and community health. The American Psychological Association declared 2000–2010 the Decade of Behavior, with a similarly broad scope. Psychological methods are considered applicable to all aspects of human life and society.

Uses

There are many uses of applied psychology and can be found as a subfield in other genres of psychology. Applied Psychology has been used in teaching psychology because it focuses on the scientific findings and how it can be used to transfer that behavior.  Many people who use applied psychology work in the fields of teaching, industrial, clinical, and consulting work areas. The Encyclopedia of Applied Psychology delves deeper into the many subsections that are used in correlation with this field and further explains the procedures that should be used in each of the respective industries.

Advertising

Main article: Advertising

Digital advertisements shown at Picadilly Circus, London at night

Business advertisers have long consulted psychologists in assessing what types of messages will most effectively induce a person to buy a particular product. The three main types of psychologists that participate in creating advertisements are cognitive, media, and social psychologists. These psychologists often work together to create advertisements that create an emotional impact on the viewer in order to make the advertisement more memorable.Using the psychological research methods and the findings in human's cognition, motivation, attitudes and decision making, those can help to design more persuasive advertisement. Their research includes the study of unconscious influences and brand loyalty. However, the effect of unconscious influences was controversial. The use of these psychologists often create successful advertisements with the scientific methods that are used to portray violence, humor and sex.

Educational

Main article: Educational psychology

Educational psychology is devoted to the study of how humans learn in educational settings, especially schools. Psychologists assess the effects of specific educational interventions: e.g., phonics versus whole language instruction in early reading attainment. They also study the question of why learning occurs differently in different situations.

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.

Counseling

Main article: Counseling psychology

Counseling psychology is an applied specialization within psychology, that involves both research and practice in a number of different areas or domains. According to Gelso and Fretz (2001), there are some central unifying themes among counseling psychologists. These include a focus on an individual's strengths, relationships, their educational and career development, as well as a focus on normal personalities. Counseling psychologists help people improve their well-being, reduce and manage stress, and improve overall functioning in their lives. The interventions used by Counseling Psychologists may be either brief or long-term in duration. Often they are problem focused and goal-directed. There is a guiding philosophy which places a value on individual differences and an emphasis on "prevention, development, and adjustment across the life-span." The use of applied psychology in counseling is one of the most useful when it comes to the treatment of individuals. The use of knowledge from scientific findings are beneficial because there are many different options that can be tested to find the right treatment.

Medical and clinical

Main articles: Medical psychology and Clinical psychology

Medical psychology

Main article: Medical psychology

Medical psychology involves the application of a range of psychological principles, theories and findings applied to the effective management of physical and mental disorders to improve the psychological and physical health of the patient. The American Psychological Association defines medical psychology as the branch of psychology that integrates somatic and psychotherapeutic modalities, into the management of mental illness, health rehabilitation and emotional, cognitive, behavioural and substance use disorders. According to Muse and Moore (2012), the medical psychologist's contributions in the areas of psychopharmacology which sets it apart from other of psychotherapy and psychotherapists.

Clinical psychology

Main article: 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 therapeutic needs met. Clinical psychologists may also work as part of a team with other professionals, such as social workers and nutritionists.

Environmental

Main article: 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.

Forensic, legal and criminal

Main articles: Forensic psychology, Legal psychology, and Criminal psychology

Forensic psychology and legal psychology are the areas 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 be criminal in nature. Forensic psychologists rarely get involved in the actual criminal investigations, which falls under a broader category of applied psychology called criminal psychology. Custody cases are an 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. Psychologists are often called to testify as expert witnesses on issues such as the accuracy of memory, the reliability of police interrogation, and the appropriate course of action in child custody cases.

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. However, 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. Some universities operate dual JD/PhD programs focusing on the intersection of these two areas.

The Committee on Legal Issues of the American Psychological Association is known to file amicus curae briefs, as applications of psychological knowledge to high-profile court cases.

A related field, police psychology, involves consultation with police departments and participation in police training.

Health and medicine

Main article: 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 aim to change health behaviors for the dual purpose of helping people stay healthy and helping patients adhere to disease treatment regimens. The focus of health psychologists tend to center on the health crisis facing the western world particularly in the US. Cognitive behavioral therapy and behavior modification are techniques often employed by health psychologists. Psychologists also study patients' compliance with their doctors' orders.

Health psychologists view a person's mental condition as heavily related to their physical condition. An important concept in this field is stress, a mental phenomenon with well-known consequences for physical health.

Occupational health psychology

Main article: Occupational health psychology

Occupational health psychology (OHP) is a relatively new discipline that emerged from the confluence of health psychology, industrial and organizational psychology, and occupational health. OHP has its own 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. Three important organizations closely associated with OHP are the International Commission on Occupational Health's Scientific Committee on Work Organisation and Psychosocial Factors (ICOH-WOPS), the Society for Occupational Health Psychology, and the European Academy of Occupational Health Psychology.

Human factors and ergonomics

Main article: Human factors and ergonomics

Human factors and ergonomics 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 complement 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 on 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 information in output. The inability of rapid and accurate corrections can sometimes lead to drastic consequences, as summed up by many stories in Set Phasers 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 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

Main article: Industrial and organizational psychology

Industrial and organizational psychology, or I-O psychology, focuses on the psychology of work. Relevant topics within I-O psychology include the psychology of recruitment, selecting employees from an applicant pool, training, performance appraisal, job satisfaction, work motivation. work behavior, occupational stress, accident prevention, occupational safety and health, management, retirement planning and unemployment among many other issues related to the workplace and people's work lives. In short, I-O psychology is the application of psychology to the workplace. One aspect of this field is job analysis, the detailed study of which behaviors a given job entails.

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 leadership, performance evaluation, training, and much more.

Military psychology includes research into the classification, training, and performance of soldiers.

School

Main article: 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 psycho-educational 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.

One salient application for school psychology in today's world is responding to the unique challenges of increasingly multicultural classrooms. For example, psychologists can contribute insight about the differences between individualistic and collectivistic cultures.

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.

Social change

Psychologists have been employed to promote "green" behavior, i.e. sustainable development. In this case, their goal is behavior modification, through strategies such as social marketing. Tactics include education, disseminating information, organizing social movements, passing laws, and altering taxes to influence decisions.

Psychology has been applied on a world scale with the aim of population control. For example, one strategy towards television programming combines social models in a soap opera with informational messages during advertising time. This strategy successfully increased women's enrollment at family planning clinics in Mexico. The programming—which has been deployed around the world by Population Communications International and the Population Media Center—combines family planning messages with representations of female education and literacy.

Sport psychology

Main article: Sport psychology

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.

Traffic psychology

Main article: Traffic psychology

Traffic psychology is an applied discipline within psychology that looks at the relationship between psychological processes and cognitions and the actual behavior of road users. In general, traffic psychologists attempt to apply these principles and research findings, in order to provide solutions to problems such as traffic mobility and congestion, road accidents, speeding. Research psychologists also are involved with the education and the motivation of road users.

Popular psychology

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Popular_psychology

Popular psychology (sometimes shortened as pop psychology or pop psych) refers to the concepts and theories about human mental life and behavior that are supposedly based on psychology and are considered credible and accepted by the wider populace. The concept is cognate with the human potential movement of the 1950s and 1960s.

The term pop psychologist can be used to describe authors, consultants, lecturers, and entertainers who are widely perceived as being psychologists, not because of their academic credentials, but because they have projected that image or have been perceived in that way in response to their work.

The term popular psychology can also be used when referring to the popular psychology industry, a sprawling network of everyday sources of information about human behavior.

The term is often used in a pejorative fashion to describe psychological concepts that appear oversimplified, out of date, unproven, misunderstood or misinterpreted; however, the term may also be used to describe professionally produced psychological knowledge, regarded by most experts as valid and effective, that is intended for use by the general public.

Types

Popular psychology commonly takes the form of:

• self-help books, for example The Road Less Travelled, by M. Scott Peck;
• advice dispensed through radio, TV, and print; for example Dear Abby, Dr. Phil and Dan Savage;
• myths such as "People use only about 10 percent of their brain's capacity";
• terminology that may have a basis in psychology, but which appears more frequently in the vernacular than in professional discourse—for example, inner child, left brain/right brain, emotional intelligence, Freudian slip, and enneagram;
• public perceptions about psychological methodologies that have not been scientifically validated, such as neuro-linguistic programming;
• urban legends such as "Psychologist B. F. Skinner raised his own daughter in a 'Skinner box' "

Self-help

Popular psychology is an essential ingredient of the self-help industry.

According to Fried and Schultis, criteria for a good self-help book include "claims made by the author as to the book's efficacy, the presentation of problem-solving strategies based on scientific evidence and professional experience, the author's credentials and professional experience, and the inclusion of a bibliography."

Three potential dangers of self-help books are:

• people may falsely label themselves as psychologically disturbed;
• people may misdiagnose themselves and use material that deals with the wrong problem;
• people may not be able to evaluate a program and may select an ineffective one;

Psychobabble

Main article: Psychobabble

The misuse and overuse of technical psychological terms is called psychobabble.

Sometimes psychological jargon is used to dress up sales pitches, self-help programs, and New Age ideas to lend these endeavors a respectable scientific appearance. Other times, people use psychological terminology to describe everyday, normal experiences in a way that pathologize a normal behavior, such as feeling sad after a loss, by suggesting that unpleasant emotions are a type of psychopathology, like major depressive disorder. People may use psychobabble because they believe that complex, descriptive or special esoteric terms more clearly or more dramatically communicate their experiences of social and personal situations, or because they believe that it makes them sound more educated.

Some terms that have an origin in psychological terminology and are typically misused include co-dependent, dysfunctional, meaningful relationship, narcissistic, antisocial, traumatic bonding, synergy, and gaslighting.

Pop psychologists

Some figures characterized at varying times as exponents of pop psychology include:

• Werner Erhard
• Phil McGraw ("Dr Phil")
• Malcolm Gladwell

History

Early movements in the history of American psychology can explain the importance our culture places on the field at large.

Rise of psychology in the United States

Beginning late in the 19th century, and largely influenced by German scholar Wilhelm Wundt, Americans including James Mckeen Cattell, G. Stanley Hall, William James, and others helped to formalize psychology as an academic discipline in the United States. Popularity in psychology grew as the public became more aware of the field. In 1890, James published The Principles of Psychology, which produced a surge of public interest. In 1892, James wrote Psychology: The Briefer Course as an opportunity for the public to read and understand psychological literature. In a similar attempt in 1895, E. W. Scripture, another American psychologist, published a book, called Thinking, Feeling, Doing, that was adapted for the average reader.

Popular misconceptions and the effort to counteract

Despite the various publications, the general public had minimal understanding of what psychologists did and what psychology was all about. Many believed psychology was "mind reading and spiritualism" and that it had no real application in everyday life. Whereas, in reality, psychology was more about studying normal human behaviors and experiences that could very well have strong applications to everyday life.

Thus, regardless of the mass interest in psychology, an accurate account of psychology for the layman was rare. Many psychologists became concerned that their profession was failing appropriately to reach the public.

In 1893, Joseph Jastrow and Hugo Münsterberg led a public exhibit on psychology in the World's Columbian Exposition in Chicago as an effort to celebrate psychology, offer information to the public, and correct popular misconceptions. The exhibit provided catalogs of information on equipment, research topics, and purposes of psychology. In a similar attempt to inform the public, the 1904 Louisiana Purchase Exposition in St. Louis included (among others) presentations from G. Stanley Hall, Edward B. Titchener, Mary Whiton Calkins, John B. Watson, and Adolph Meyer. The exhibits also included public testing and experimentation.

Although admirable, the attempt to seek public approval failed to make a significant impact and psychologists became more concerned about their public image. In 1900, Jastrow wrote a book entitled Fact and Fable in Psychology that aimed to resolve popular psychological misconceptions by clearly discerning fact from fable. In preface to his book, Jastrow states, "It is a matter of serious concern that the methods of genuine psychology, that the conditions of advance in psychology, that the scope and nature of its problems should be properly understood."

Popularization of psychology

It was not until the more powerful movement of applied psychology that popularity in psychology grew to affect people's everyday lives. The work of G. Stanley Hall in educational psychology led changes in the approaches of teaching and the Child-Study movement, supported in experimental psychology, and guided educational reform.

Several critics warned that applying experimental psychology to education may be problematic. In 1898, Münsterberg wrote a controversial article entitled "The Danger from Experimental Psychology" in which he claims the impossible transfer of experimental results into successful teaching practices.

Despite the disagreements, popular culture grasped onto the implications in the field of applied psychology with the hope that the research could improve their lives. Early applications included clinical psychology, business, industrial psychology, and the psychology of advertising. Furthermore, the onset of World War I led to advances in psychology brought about by its application in military psychology.

The media provided the public more accessible psychological information through the publication of countless books and popular magazines including Harpers, Forum, Atlantic Monthly, and Colliers. After WWI, demand grew for a more frequent source of popular psychology and newspapers became a primary source of public information. In fact, newspaper columns were so well-received that professional psychologist Jastrow had a column entitled Keeping Mentally Fit that appeared in more than 150 newspapers in the 1920s.

Soon, public demand for psychological services and information grew so fierce that the availability of legitimate research and real psychologists became insufficient. Consequently, nonprofessionals began to offer their services under the guise of psychologists.

The American Psychological Association (APA) responded with an effort to establish official certifications for trained psychologists. However, popular interest overlooked the qualifications and eagerly sought to apply popular psychological science regardless of its validity.

Short-lived, the excitement over useful psychology was curbed by articles warning of the exaggerated and false claims made by popular psychology. Stephen Leacock described the changing popularity in psychology in 1924, stating,

As part of the new researches, it was found that psychology can be used... for almost everything in life. There is now not only psychology in the academic or college sense, but also a Psychology of Business, Psychology of Education, a Psychology of Salesmanship, a Psychology of Religion... and a Psychology of Playing the Banjo. In short, everybody has his.

Others authored similar cautions to the public and, among the most recursive, was that of Grace Adams (psychologist) who, in her 1928 article, wrote

a vociferous attack on applied psychology [and] argued that psychology had forsaken its scientific roots so that individual psychologists might achieve popularity and prosperity.

After the Depression hit in 1929, popular literature began to decline while scientific publications in periodicals increased. This discrepancy between the public sector and academia supported the popular belief that professional psychologists were not interested in solving America's problems. The lack of professional participation provided pseudoscientific and unprofessional psychological literature to become very popular. In the 1930s, self-help books and the publication of three magazines (Modern Psychologist, Practical Psychology Monthly, and Psychology Digest) became part of a popular psychology movement.

World War II gave professional psychology another chance to prove its value as a science with an increase in professional opportunities. In the article "Don't They Understand Us? A history of Psychology's Public Image", Benjamin describes the direction of psychology at the time:

The praise psychologists received from government, industry, and the military provided a tremendous boost for the public image of psychology... Yet many contemporary psychologists are concerned that the current image is far from acceptable and that the science and profession of psychology continues to suffer because of that image.

Current status of popular psychology

In his Presidential Address to the APA in 1969, George Armitage Miller was hopeful for psychology's future stating, "that the real impact of psychology will be felt, ... through its effects on the public at large, through a new and different public conception of what is humanly possible and what is humanly desirable."

Current events influence the popularity of areas in psychology. During 2020 and 2021 many of the most popular psychology articles were about COVID-19 and even Zoom fatigue. The APA's most downloaded journal articles frequently include research about social media. Social media frequently spreads misinformation about health, and this could extend to mental health misinformation. Psychobabble can be used on social media to spread this misinformation. However, social media can be a place where pop psychology is used to spread mental health awareness.

Limits and criticism

A June 2023 article by Vox Media explored the limits of pop psychology terms ("therapy speak") saying "people become attached to terms that encapsulate certain events and people, to varying degrees, in order to bolster an argument or justify an experience. Having common language to describe a difficult situation can help people more effectively communicate their concerns and garner support, but these terms can just as easily be weaponized."

Object recognition (cognitive science)

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Object_recognition_(cognitive_science)

Visual object recognition refers to the ability to identify the objects in view based on visual input. One important signature of visual object recognition is "object invariance", or the ability to identify objects across changes in the detailed context in which objects are viewed, including changes in illumination, object pose, and background context.

Basic stages of object recognition

Neuropsychological evidence affirms that there are four specific stages identified in the process of object recognition. These stages are:

Stage 1 Processing of basic object components, such as color, depth, and form.

Stage 2 These basic components are then grouped on the basis of similarity, providing information on distinct edges to the visual form. Subsequently, figure-ground segregation is able to take place.

Stage 3 The visual representation is matched with structural descriptions in memory.

Stage 4 Semantic attributes are applied to the visual representation, providing meaning, and thereby recognition.

Within these stages, there are more specific processes that take place to complete the different processing components. In addition, other existing models have proposed integrative hierarchies (top-down and bottom-up), as well as parallel processing, as opposed to this general bottom-up hierarchy.

Hierarchical recognition processing

Visual recognition processing is typically viewed as a bottom-up hierarchy in which information is processed sequentially with increasing complexities. During this process, lower-level cortical processors, such as the primary visual cortex, are at the bottom of the hierarchy. Higher-level cortical processors, such as the inferotemporal cortex (IT), are at the top, where visual recognition is facilitated. A highly recognized bottom-up hierarchical theory is James DiCarlo's Untangling description  whereby each stage of the hierarchically arranged ventral visual pathway performs operations to gradually transform object representations into an easily extractable format. In contrast, an increasingly popular recognition processing theory, is that of top-down processing. One model, proposed by Moshe Bar (2003), describes a "shortcut" method in which early visual inputs are sent, partially analyzed, from the early visual cortex to the prefrontal cortex (PFC). Possible interpretations of the crude visual input is generated in the PFC and then sent to the inferotemporal cortex (IT) subsequently activating relevant object representations which are then incorporated into the slower, bottom-up process. This "shortcut" is meant to minimize the number of object representations required for matching thereby facilitating object recognition. Lesion studies have supported this proposal with findings of slower response times for individuals with PFC lesions, suggesting use of only the bottom-up processing.

Object constancy and theories of object recognition

"Object constancy" redirects here. For the understanding that objects still exist when not perceived, see object permanence.

A significant aspect of object recognition is that of object constancy: the ability to recognize an object across varying viewing conditions. These varying conditions include object orientation, lighting, and object variability (size, color, and other within-category differences). For the visual system to achieve object constancy, it must be able to extract a commonality in the object description across different viewpoints and the retinal descriptions.[9] Participants who did categorization and recognition tasks while undergoing a functional magnetic found as increased blood flow indicating activation in specific regions of the brain. The categorization task consisted of participants placing objects from canonical or unusual views as either indoor or outdoor objects. The recognition task occurs by presenting the participants with images that they had viewed previously. Half of these images were in the same orientation as previously shown, while the other half were presented in the opposing viewpoint. The brain regions implicated in mental rotation, such as the ventral and dorsal visual pathways and the prefrontal cortex, showed the greatest increase in blood flow during these tasks, demonstrating that they are critical for the ability to view objects from multiple angles. Several theories have been generated to provide insight on how object constancy may be achieved for the purpose of object recognition including, viewpoint-invariant, viewpoint-dependent and multiple views theories.

Viewpoint-invariant theories

Viewpoint-invariant theories suggest that object recognition is based on structural information, such as individual parts, allowing for recognition to take place regardless of the object's viewpoint. Accordingly, recognition is possible from any viewpoint as individual parts of an object can be rotated to fit any particular view. This form of analytical recognition requires little memory as only structural parts need to be encoded, which can produce multiple object representations through the interrelations of these parts and mental rotation. Participants in a study were presented with one encoding view from each of 24 preselected objects, as well as five filler images. Objects were then represented in the central visual field at either the same orientation or a different orientation than the original image. Then participants were asked to name if the same or different depth- orientation views of these objects presented. The same procedure was then executed when presenting the images to the left or right visual field. Viewpoint-dependent priming was observed when test views were presented directly to the right hemisphere, but not when test views were presented directly to the left hemisphere. The results support the model that objects are stored in a manner that is viewpoint dependent because the results did not depend on whether the same or a different set of parts could be recovered from the different-orientation views.

3-D model representation

This model, proposed by Marr and Nishihara (1978), states that object recognition is achieved by matching 3-D model representations obtained from the visual object with 3-D model representations stored in memory as vertical shape precepts. Through the use of computer programs and algorithms, Yi Yungfeng (2009) was able to demonstrate the ability for the human brain to mentally construct 3D images using only the 2D images that appear on the retina. Their model also demonstrates a high degree of shape constancy conserved between 2D images, which allow the 3D image to be recognized. The 3-D model representations obtained from the object are formed by first identifying the concavities of the object, which separate the stimulus into individual parts. Recent research suggests that an area of the brain, known as the caudal intraparietal area (CIP), is responsible for storing the slant and tilt of a plan surface that allow for concavity recognition. Rosenburg et al. implanted monkeys with a scleral search coil for monitoring eye position while simultaneously recording single neuron activation from neurons within the CIP. During the experiment, monkeys sat 30 cm away from an LCD screen that displayed the visual stimuli. Binocular disparity cues were displayed on the screen by rendering stimuli as green-red anaglyphs and the slant-tilt curves ranged from 0 to 330. A single trial consisted of a fixation point and then the presentation of a stimulus for 1 second. Neuron activation were then recorded using the surgically inserted micro electrodes. These single neuron activation for specific concavities of objects lead to the discovery that each axis of an individual part of an object containing concavity are found in memory stores. Identifying the principal axis of the object assists in the normalization process via mental rotation that is required because only the canonical description of the object is stored in memory. Recognition is acquired when the observed object viewpoint is mentally rotated to match the stored canonical description.

Figure 1. This image, created based on Biederman's (1987) Recognition by Components theory, is an example of how objects can be broken down into Geons.

Recognition by components

An extension of Marr and Nishihara's model, the recognition-by-components theory, proposed by Biederman (1987), proposes that the visual information gained from an object is divided into simple geometric components, such as blocks and cylinders, also known as "geons" (geometric ions), and are then matched with the most similar object representation that is stored in memory to provide the object's identification (see Figure 1).

Viewpoint-dependent theories

Viewpoint-dependent theories suggest that object recognition is affected by the viewpoint at which it is seen, implying that objects seen in novel viewpoints reduce the accuracy and speed of object identification. This theory of recognition is based on a more holistic system rather than by parts, suggesting that objects are stored in memory with multiple viewpoints and angles. This form of recognition requires a lot of memory as each viewpoint must be stored. Accuracy of recognition also depends on how familiar the observed viewpoint of the object is.

Multiple views theory

This theory proposes that object recognition lies on a viewpoint continuum where each viewpoint is recruited for different types of recognition. At one extreme of this continuum, viewpoint-dependent mechanisms are used for within-category discriminations, while at the other extreme, viewpoint-invariant mechanisms are used for the categorization of objects.

Neural substrates

The Dorsal Stream is shown in green and the Ventral Stream in purple.

The dorsal and ventral stream

The visual processing of objects in the brain can be divided into two processing pathways: the dorsal stream (how/where), which extends from the visual cortex to the parietal lobes, and ventral stream (what), which extends from the visual cortex to the inferotemporal cortex (IT). The existence of these two separate visual processing pathways was first proposed by Ungerleider and Mishkin (1982) who, based on their lesion studies, suggested that the dorsal stream is involved in the processing of visual spatial information, such as object localization (where), and the ventral stream is involved in the processing of visual object identification information (what). Since this initial proposal, it has been alternatively suggested that the dorsal pathway should be known as the 'How' pathway as the visual spatial information processed here provides us with information about how to interact with objects, For the purpose of object recognition, the neural focus is on the ventral stream.

Functional specialization in the ventral stream

Within the ventral stream, various regions of proposed functional specialization have been observed in functional imaging studies. The brain regions most consistently found to display functional specialization are the fusiform face area (FFA), which shows increased activation for faces when compared with objects, the parahippocampal place area (PPA) for scenes vs. objects, the extrastriate body area (EBA) for body parts vs. objects, MT+/V5 for moving stimuli vs. static stimuli, and the Lateral Occipital Complex (LOC) for discernible shapes vs. scrambled stimuli. (See also: Neural processing for individual categories of objects)

Structural processing: the lateral occipital complex

The lateral occipital complex (LOC) has been found to be particularly important for object recognition at the perceptual structural level. In an event-related [fMRI-en] study that looked at the adaptation of neurons activated in visual processing of objects, it was discovered that the similarity of an object's shape is necessary for subsequent adaptation in the LOC, but specific object features such as edges and contours are not. This suggests that activation in the LOC represents higher-level object shape information and not simple object features. In a related [fMRI-en] study, the activation of the LOC, which occurred regardless of the presented object's visual cues such as motion, texture, or luminance contrasts, suggests that the different low-level visual cues used to define an object converge in "object-related areas" to assist in the perception and recognition process. None of the mentioned higher-level object shape information seems to provide any [semantic-en] information about the object as the LOC shows a neuronal response to varying forms including non-familiar, abstract objects.

Further experiments have proposed that the LOC consists of a hierarchical system for shape selectivity indicating greater selective activation in the posterior regions for fragments of objects whereas the [anterior-en] regions show greater activation for full or partial objects. This is consistent with previous research that suggests a hierarchical representation in the ventral temporal cortex where primary feature processing occurs in the posterior regions and the integration of these features into a whole and meaningful object occurs in the [anterior-en] regions.

Semantic Processing

Semantic associations allow for faster object recognition. When an object has previously been associated with some sort of semantic meaning, people are more prone to correctly identify the object. Research has shown that semantic associations allow for a much quicker recognition of an object, even when the object is being viewed at varying angles. When objects are viewed at increasingly deviated angles from the traditional plane of view, objects that held learned semantic associations had lower response times compared to objects that did not hold any learned semantic associations. Thus, when object recognition becomes increasingly difficult, semantic associations allow recognition to be much easier. Similarly, a subject can be primed to recognize an object by observing an action that is simply related to the target object. This shows that objects have a set of sensory, motor and semantic associations that allow a person to correctly recognize an object. This supports the claim that the brain utilizes multiple parts when trying to accurately identify an object.

Through information provided from [neuropsychological-en] patients, dissociation of recognition processing have been identified between structural and [semantic-en] processing as structural, colour, and associative information can be selectively impaired. In one PET study, areas found to be involved in associative semantic processing include the left anterior superior/middle temporal gyrus and the left temporal pole comparative to structural and colour information, as well as the right temporal pole comparative to colour decision tasks only. These results indicate that stored perceptual knowledge and semantic knowledge involve separate cortical regions in object recognition as well as indicating that there are hemispheric differences in the temporal regions.

Research has also provided evidence which indicates that visual semantic information converges in the fusiform gyri of the inferotemporal lobes. In a study that compared the semantic knowledge of category versus attributes, it was found that they play separate roles in how they contribute to recognition. For categorical comparisons, the lateral regions of the fusiform gyrus were activated by living objects, in comparison to nonliving objects which activated the medial regions. For attribute comparisons, it was found that the right fusiform gyrus was activated by global form, in comparison to local details which activated the left fusiform gyrus. These results suggest that the type of object category determines which region of the fusiform gyrus is activated for processing semantic recognition, whereas the attributes of an object determines the activation in either the left or right fusiform gyrus depending on whether global form or local detail is processed.

In addition, it has been proposed that activation in [anterior-en] regions of the fusiform gyri indicate successful recognition. However, levels of activation have been found to depend on the semantic relevance of the object. The term semantic relevance here refers to "a measure of the contribution of semantic features to the core meaning of a concept." Results showed that objects with high semantic relevance, such as artefacts, created an increase in activation compared to objects with low semantic relevance, such as natural objects. This is due to the proposed increased difficulty to distinguish between natural objects as they have very similar structural properties which makes them harder to identify in comparison to artefacts. Therefore, the easier the object is to identify, the more likely it will be successfully recognized.

Another condition that affects successful object recognition performance is that of contextual facilitation. It is thought that during tasks of object recognition, an object is accompanied by a "context frame", which offers semantic information about the object's typical context. It has been found that when an object is out of context, object recognition performance is hindered with slower response times and greater inaccuracies in comparison to recognition tasks when an object was in an appropriate context. Based on results from a study using [fMRI-en], it has been proposed that there is a "context network" in the brain for contextually associated objects with activity largely found in the Parahippocampal cortex (PHC) and the Retrosplenial Complex (RSC). Within the PHC, activity in the Parahippocampal Place Area (PPA), has been found to be preferential to scenes rather than objects; however, it has been suggested that activity in the PHC for solitary objects in tasks of contextual facilitation may be due to subsequent thought of the spatial scene in which the object is contextually represented. Further experimenting found that activation was found for both non-spatial and spatial contexts in the PHC, although activation from non-spatial contexts was limited to the [anterior-en] PHC and the posterior PHC for spatial contexts.

Recognition memory

When someone sees an object, they know what the object is because they've seen it on a past occasion; this is recognition memory. Not only do abnormalities to the ventral (what) stream of the visual pathway affect our ability to recognize an object but also the way in which an object is presented to us. One notable characteristic of visual recognition memory is its remarkable capacity: even after seeing thousands of images on single trials, humans perform at high accuracy in subsequent memory tests and they remember considerable detail about the images that they have seen.

Context

Context allows for a much greater accuracy in object recognition. When an identifiable object is blurred, the accuracy of recognition is much greater when the object is placed in a familiar context. In addition to this, even an unfamiliar context allows for more accurate object recognition compared to the object being shown in isolation. This can be attributed to the fact that objects are typically seen in some setting rather than no setting at all. When the setting the object is in is familiar to the viewer, it becomes much easier to determine what the object is. Though context is not required to correctly recognize, it is part of the association that one makes with a certain object.

Context becomes especially important when recognizing faces or emotions. When facial emotions are presented without any context, the ability to which someone is able to accurately describe the emotion being shown is significantly lower than when context is given. This phenomenon remains true across all age groups and cultures, signifying that context is essential in accurately identifying facial emotion for all individuals.

Familiarity

Familiarity is a mechanism that is context-free in the sense that what one recognizes just feels familiar without spending time trying to find in what context one knows the object. The ventro-lateral region of the frontal lobe is involved in memory encoding during incidental learning and then later maintaining and retrieving semantic memories. Familiarity can induce perceptual processes different from those of unfamiliar objects which means that our perception of a finite number of familiar objects is unique. Deviations from typical viewpoints and contexts can affect the efficiency for which an object is recognized most effectively. It was found that not only are familiar objects recognized more efficiently when viewed from a familiar viewpoint opposed to an unfamiliar one, but also this principle applies to novel objects. This deduces to the thought that representations of objects in our brain are organized in more of a familiar fashion of the objects observed in the environment. Recognition is not only largely driven by object shape and/or views but also by dynamic information. Familiarity can benefit the perception of dynamic point-light displays, moving objects, the sex of faces, and face recognition.

Recollection

Recollection shares many similarities with familiarity; however, it is context-dependent, requiring specific information from the inquired incident.

Impairments

Loss of object recognition is called visual object agnosia. There are two broad categories of visual object agnosia: apperceptive and associative. When object agnosia occurs from a lesion in the dominant hemisphere, there is often a profound associated language disturbance, including loss of word meaning.

Effects of lesions in the ventral stream

Object recognition is a complex task and involves several different areas of the brain – not just one. If one area is damaged then object recognition can be impaired. The main area for object recognition takes place in the temporal lobe. For example, it was found that lesions to the perirhinal cortex in rats causes impairments in object recognition especially with an increase in feature ambiguity. Neonatal aspiration lesions of the amygdaloid complex in monkeys appear to have resulted in a greater object memory loss than early hippocampal lesions. However, in adult monkeys, the object memory impairment is better accounted for by damage to the perirhinal and entorhinal cortex than by damage to the amygdaloid nuclei. Combined amygdalohippocampal (A + H) lesions in rats impaired performance on an object recognition task when the retention intervals were increased beyond 0s and when test stimuli were repeated within a session. Damage to the [amygdala-en] or [hippocampus-en] does not affect object recognition, whereas A + H damage produces clear deficits. In an object recognition task, the level of discrimination was significantly lower in the electrolytic lesions of globus pallidus (part of the basal ganglia) in rats compared to the Substantia- Innominata/Ventral Pallidum which was in turn worse compared to Control and Medial Septum/Vertical Diagonal Band of Broca groups; however, only globus pallidus did not discriminate between new and familiar objects. These lesions damage the ventral (what) pathway of the visual processing of objects in the brain.

Visual agnosias

Agnosia is a rare occurrence and can be the result of a stroke, dementia, head injury, brain infection, or hereditary. Apperceptive agnosia is a deficit in object perception creating an inability to understand the significance of objects. Similarly, associative visual agnosia is the inability to understand the significance of objects; however, this time the deficit is in semantic memory. Both of these agnosias can affect the pathway to object recognition, like Marr's Theory of Vision. More specifically unlike apperceptive agnosia, associative agnosic patients are more successful at drawing, copying, and matching tasks; however, these patients demonstrate that they can perceive but not recognize. Integrative agnosia(a subtype of associative agnosia) is the inability to integrate separate parts to form a whole image. With these types of agnosias there is damage to the ventral (what) stream of the visual processing pathway. Object orientation agnosia is the inability to extract the orientation of an object despite adequate object recognition. With this type of agnosia there is damage to the dorsal (where) stream of the visual processing pathway. This can affect object recognition in terms of familiarity and even more so in unfamiliar objects and viewpoints. A difficulty in recognizing faces can be explained by prosopagnosia. Someone with prosopagnosia cannot identify the face but is still able to perceive age, gender, and emotional expression. The brain region that specifies in facial recognition is the fusiform face area. Prosopagnosia can also be divided into apperceptive and associative subtypes. Recognition of individual chairs, cars, animals can also be impaired; therefore, these object share similar perceptual features with the face that are recognized in the fusiform face area.

Alzheimer's disease

The distinction between category and attribute in semantic representation may inform our ability to assess semantic function in aging and disease states affecting semantic memory, such as Alzheimer's disease (AD). Because of semantic memory deficits, persons with Alzheimer's disease have difficulties recognizing objects as the semantic memory is known to be used to retrieve information for naming and categorizing objects. In fact, it is highly debated whether the semantic memory deficit in AD reflects the loss of semantic knowledge for particular categories and concepts or the loss of knowledge of perceptual features and attributes.

Emotional lateralization

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Emotional_lateralization 

Emotional lateralization is the asymmetrical representation of emotional control and processing in the brain. There is evidence for the lateralization of other brain functions as well.

Emotions are complex and involve a variety of physical and cognitive responses, many of which are not well understood. The general purpose of emotions is to produce a specific response to a stimulus. Feelings are the conscious perception of emotions, and when an emotion occurs frequently or continuously this is called a mood.

A variety of scientific studies have found lateralization of emotions. FMRI and lesion studies have shown asymmetrical activation of brain regions while thinking of emotions, responding to extreme emotional stimuli, and viewing emotional situations. Processing and production of facial expressions also appear to be asymmetric in nature. Many theories of lateralization have been proposed and some of those specific to emotions. Please keep in mind that most of the information in this article is theoretical and scientists are still trying to understand emotion and emotional lateralization. Also, some of the evidence is contradictory. Many brain regions are interconnected and the input and output of any given region may come from and go to many different regions.

Theories of lateralization

Right hemisphere dominance

Some variations of right hemisphere dominance are...
a) The right hemisphere has more control over emotion than left hemisphere.
b) The right hemisphere is dominant in emotional expression in a similar way that the left hemisphere is dominant in language.
c) The right hemisphere is dominant in the perception of facial expression, body posture, and prosody.
d) The right hemisphere is important for processing primary emotions such as fear while the left hemisphere is important for preprocessing social emotions. 

General lesions in the right hemisphere reduce or eliminate electrodermal response (skin conductance response ((SCR)) to emotionally meaningful stimuli while the lesions in the left hemisphere do not show changes in SCR response.

Subject SB-2046 had part of his right, prefrontal lobe removed because of cancer. While his IQ and a majority of other normal functions were unharmed, he had severely impaired decision-making skills especially when he had to consider immediate vs. future reward and punishment. His decisions were almost always guided by immediate reward or punishment and disregarded any long-term consequences. Researchers were incapable of conditioning patient SB-2046 to nonverbal stimuli containing emotional meaning (reward or punishment), but were able to condition the patient to verbal stimuli containing emotional meaning.

Most language production and processing occur in the left hemisphere while the majority of the emotional processing and production of emotion in speech occurs in the right hemisphere. Persons with schizophrenia usually have difficulty processing prosody. These patients also show a remarkable increase in lateralization towards the right hemisphere of both emotionally and non-emotional prosody rich speech. Also, a decrease in right-handedness led to an increase in the right hemisphere lateralization. This right hemisphere lateralization extends beyond prosody to many of aspects of language and speech processing in schizophrenic patients.

Complementarity specialization

The two hemispheres have a complementary specialization for control of different aspects of emotion.
Left hemisphere primarily process "positive" emotions and right hemisphere primarily process "negative" emotions. A large portion of regions primarily in the right hemisphere are activated during aversive classical conditioning.

While this theory seems to hold true for some emotions, this theory is generally considered outdated; however a few examples exist. For example, a study found that when subjects were primed with positive stimuli before hearing a consonant, the left hemisphere was more active than the right hemisphere. In contrast, when subjects were primed with a negative stimulus, the right hemisphere was more active than the left hemisphere.

b) Other divisions of specialization

The amygdala plays a role in the conscious awareness of emotion (feelings) resulting in perception of feeling, but experiments suggest the left and right amygdala have distinct roles in conscious and unconscious processing of emotion. The right amygdala plays a role in the nonconscious processing of emotion while the left amygdala was involved in the processing of conscious emotions. These results were obtained from studies that masked conditioning stimuli. Stimuli were presented over a very short period of time such that subjects were not consciously aware of the stimuli but were still able to show physiological changes.

Damage to the left hemisphere in patients results in a marked increase in depression. Valence asymmetry may be due to more cholinergic and dopaminergic on the left hemisphere and the right hemisphere being more noradrenergic. Patients with right hemisphere damage had reduced arousal response to painful stimuli.

Homeostatic basis

Neuroanatomical basis for emotional lateralization

This model provides a neuroanatomical basis for emotional control and processing. The peripheral autonomic nervous system is not symmetrical. Afferent nerves in the parasympathetic and sympathetic systems of the autonomic nervous system differently innervate various organs that maintain homeostasis such as the heart and the face. The asymmetrical representation of the autonomic peripheral nervous system leads to the asymmetrical representation in the brain. The left hemisphere is activated predominantly by homeostatic afferents associated with parasympathetic functions and the right hemisphere is activated predominantly by homeostatic afferents associated with sympathetic functions. The lateralization is extremely apparent in the anterior cingulate cortex (ACC) and anterior insular cortex (AI) associated with higher emotions such as romantic love and motivation correlated with homeostatic functions. The left AI and ACC are more active during feelings of romantic love and maternal attachment. The AI and ACC were activated on both the right and left sides while watching pain being inflicted on a loved one while only the right AI and ACC that is elicited during subjective feelings of pain; this supports the association of right AI in aroused ('sympathetic') feelings and left AI in affiliative ('parasympathetic') feelings.

Particularly, cardiovascular function appears to be lateralized and tied to emotional stress. Intense emotional stimuli that cause stress can lead to alterations in cardiovascular function. The right insular cortex probably plays the most significant role in these phenomena. Similar lateralization is probably involved in cardiovascular malfunction in patients with head injury, stroke, multiple sclerosis, brain tumors, meningitis and encephalitis, migraine, cluster headache and neurosurgical procedures.

Lateralization due to lateralization of other functions

"It is unlikely that the brain evolved an asymmetrical control of emotional behavior. Rather, it seems more likely that although there may be some asymmetry in the neural control of emotion, the observed asymmetries are largely a product of the asymmetrical control of other functions such as the control of movement, language, or the processing of complex sensory information," Lateralization may have been evolutionarily adaptive. Lateralization may allow for a greater variety of emotions. The left temporal cortex is involved in language processing while the right temporal cortex is involved in processing faces. This lateralization is also apparent when processing emotions.

Lateralization and sex differences

There may be a difference in cortical activation between men and women. Activity in the right hemisphere was greater in women when exposed to unpleasant images than men, though men showed more activation bilaterally while viewing pleasant pictures. Another study found that women but not men, with women had greater activation of their right hemisphere while viewing unpleasant faces and left hemisphere activation while viewing pleasant faces. Yet, another study found contrasting sex difference while recording EEG waves in the parietal and frontal lobes. Negative pictures activated the left hemisphere in women more than in men, and the right hemisphere in men more than in women when shown unpleasant images.

Evidence of lateralization

The vast majority of the data comes from functional imaging, skin conductance response (SCR), standardized tests ranging from cognitive (e.g. IQ tests) to emotional intelligence, and subjective questionnaires such as those rating how fearful or happy faces look. All the tests have their strengths and weakness (see "Limitation of Studies" below). This section primarily focuses on results on the more subjective observations and results that have unknown neural basis or regions.

Behavioral differences and cortical activation

70% of right handed patients show preference in viewing emotion expressed on the right side of the face (in the left field of view) according to studies using chimeric faces produced using right-right or left-left mirrored faces. The left side of the face seems more fluent in expressing emotions which means the right cortical hemisphere is more fluent in expressing emotions. Handedness does not appear to affect the processing associated with viewing facial expressions.

Situations that contradict moral teachings generally produce negative emotions. Watching people behave badly by breaking moral codes most significantly activates the right parahippocampal gyrus, the right medial frontal gyrus, and left amygdala. Watching emotionally negative situations most significantly activates the right amygdala. This study indicates that lateral processing of emotions extends beyond the basic emotions to higher cognitive responses.

Depression or having previously been depressed probably is due to altered brain structure or alters brain structure. Patients who have been depressed or are depressed show more activation to negative stimuli in emotion. When negative stimuli were presented to patients' right hemispheres, the patients were significantly more accurate and quicker to respond to the stimuli. The data in this study shows that psychological disorders are correlated with increased lateralization.

Facial expressions of emotion

Patients with damage to their left amygdala lesions rated fearful faces less fearful than normal subjects. Similar findings showed that regional blood flow increased in response to fear faces while decreased to euphoric faces in the left amygdala.

Chimpanzees, other primates, and humans produce asymmetrical facial expressions with greater expression on the left side of the face (right hemisphere of the brain). Researchers also subjectively reported that the left side of the face was expressing more emotion using images of left-left chimeric faces.

Notable lateralized brain structures and regions

Emotion is processed in many different areas of the brain, and a specific emotion may be processed in multiple areas. Regions involved in emotional lateralization appear to follow the general conventions that describe the roles/functions of certain brain regions. Below are a few regions and structure involved in emotional processing that show functional lateralization.

Frontal lobe

Using a PET scan, researchers found that activity in the left medial and lateral prefrontal cortex was reciprocally associated with decrease activity in the amygdala. These findings imply that the prefrontal cortex modulates the amygdala activity. The left prefrontal cortex plays a role in approach behaviors (positively valenced emotions), while the amygdala plays a role in withdrawal behaviors (negatively valenced emotions).

The superior frontal gyrus is the most significantly activated region while processing sadness.

Patients with inferior frontal lobe damage produce less and less intense facial expression when presented with emotional stimuli, and they also have problems reading fear and disgust in other people. People with left inferior frontal lobe damage produced less facial expression and could not analyze emotional situations as well as those with right frontal lobe damage especially with fear and disgust. The left inferior frontal gyrus (IFG) plays an important role in anger while the right IFG plays a larger role in disgust.

Patients with dorsolateral frontal cortex lesions have difficulty discerning propositional attitude. Patients with left lesions show further increased impairment.

Parietal lobe

Damage to the inferior parietal region including the anterior (supramarginal gyrus) and posterior (angular gyrus) regions resulted in reduced SCR. Damage to the right hemisphere in these regions resulted in a significant (p < 0.001) decrease in SCR while the damage to the left hemisphere of these regions did not (p > 0.05).

Temporal lobe

The right superior temporal gyrus was the most significantly activated area during the processing happiness. The right superior temporal gyrus increasingly responds to an increasingly happy stimuli, while the left pulvinar increasingly responds to increasingly fearful stimuli. The right pulvinar is activated during aversive conditioning.

Amygdala

The amygdala plays a key role in emotional processing especially fear, and amygdala function appears to be emotionally lateralized. When people are shown fearful faces the left amygdala and left periamygdaloid cortex increase in activation. There also appears to be a greater increase in neural activity in the left amygdala corresponding to an increasingly fearful stimulus. Recordings from single-unit electrodes in monkeys have shown similar activation in the left amygdala. A man with confined damage in the right amygdala could not produce a startle response. The activity (measured by a PET scan) in the right amygdala correlated to the number of emotionally arousing film clips capable of being recalled in patients.

Unilateral activation of the amygdala due to fearful stimuli may also produce unilateral activation of other regions. The right middle temporal gyrus, right brainstem, left hippocampus, right cerebellum, right fuisform gyrus, and left lingual gyrus were also activated during fearful stimuli. Activation of multiple brain regions both indicates that emotions are processed in many parts of the brain and that emotions are complex.

The amygdala probably plays a role in the conscious processing of emotion. The left amygdala was activated during the processing of conscious stimuli while the right amygdala was active during the processing of nonconscous stimuli.

Anterior cingulate cortex (ACC)

The anterior cingulate cortex (ACC) plays a role in a variety of functions including emotional ones. The ACC may be important in conscious awareness of emotion. Damage to the ACC is associated with decreased SCR to physical and psychological stimuli. Bilateral and unilateral damage both resulted in decreased SCR indicates that the right and left ACC's may specialized in certain aspects of emotional response.

Anterior insula (AI)

The left anterior insula (AI) increasingly responds to increasingly fearful stimuli. The AI may also be involved in the conscious experience of emotion.

Implications

Phenomena such as emotional lateralization may help describe how emotions arise, persist, and alter our behavior. Understanding emotional lateralization will help scientists understand emotion in general. Emotional lateralization may also play a role in psychological disorders such as depression and schizophrenia. Future treatment of psychological disorders may have more targeted neurological treatments rather than ingested drugs.

Symptoms that arise from confined regions of damage usually have stereotypical emotional and behavioral changes. Diagnosis for locating damaged regions that process emotion may aided by noticeable emotional changes categorized under one of the lateralized emotional control systems. Diagnosis and treatment for cardiovascular irregularities that arises from emotions states could be aided by understanding the physical basis of the psychological influences. Instead of treating the cardiovascular irregularities for psychological issues, treatment could target the lateralized brain regions.

Limitation of Studies

Like all human based scientific experiments there are limitations to what researchers can do. Attempting to study emotions is especially hard since emotions are complex and can lead to subjective response. Since the majority of experiments in emotional lateralization have been on fear this leaves the question of whether other emotions are also lateralized. Below are two major issues associated with many of the experiments studying emotion that require further explanation.

Sample size

A large percent of the human studies are of anomalies due to accidents, tumors, or attempts to cure disease (e.g. seizures) using lesioning. Since very few such cases exist the sample size of human studies of emotional lateralization are generally very limited and may be as small as single person. While these studies may provide a good insight into certain brain regions and their functions their conclusions are not definite. Animal studies may help in understanding this problem but emotions in humans are generally considered more complicated than in most animals.

Functional imaging

There are several limitations when using fMRI or PET to study emotional responses. Because fMRI measures changes in blood oxygenation, using the BOLD effect, its temporal resolution is limited by the haemodynamic response to several seconds. PET has similar limits, offering slightly better temporal resolution and slightly worse spatial resolution.

Lesioning

Lesions rarely are localized and can affect large areas of the brain. Processing in the brain is generally not localized and requires many areas of the brain to process. Furthermore, lesioning may interfere with pathways that span the lesion site. Thus, lesions are not always a good way to determine what specific brain areas do. Therefore, a degree of skepticism should be kept in mind when viewing lateralization data from lesion studies.