A conversation is a two-way street. When one person is speaking, the other responds with nods of the head and so-called verbal nods, such as “mhm” and “uh-huh.”

Humans also tend to look into each other’s eyes during a conversation. The authors of the recent study believe that blinking conveys a message that we can subconsciously read and understand. They have publishedTrusted Source their findings in the journal PLOS One.

The researchers theorized that if blinks do carry information, altering their duration might make a difference to how an individual involved in a conversation might behave.

For their experiment, the scientists used virtual reality. Participants talked to an avatar that acted as a “virtual listener.” The avatar would ask questions — such as, “How was your weekend, what did you do?” — and the participant would respond accordingly.

The avatar, when “listening” to responses, would nod along in a manner modeled on real-life conversations.

For some of the sessions, the avatar’s blinks were short, lasting 208 milliseconds. For others, they were longer, lasting 607 milliseconds. The durations were based on blinks measured in standard conversations, so neither were unusual.

When asked, the participants did not perceive any differences between the blink durations, but subconsciously, they do seem to have taken note.

When the avatar’s blinks were longer, the participants’ answers were several seconds shorter.

This gives weight to the scientists’ theory that blinking is another type of nonverbal clue that plays a part in conversations. The authors believe that a longer blink may signify understanding. They conclude:

“Our findings show that one of the subtlest of human movements — eye blinking — appears to have a surprising effect on the coordination of everyday human interaction.”

Many of us do not give blinking much thought, but scientists have pondered its function over the years. For instance, studies have shown that we blink moreTrusted Source when we are experiencing a high cognitive load than when our brains are not being taxed.

Also, researchers examining brain activity in relation to blink rate have concluded that a high blink rate can signify a disengagement of attention.

Perhaps tellingly, one study assessing blink rates during different tasks found that people blink mostTrusted Source during conversation.

Even more tellingly, another study found that when listening during a conversation, rather than blinking randomly, we tend to blink at the end of sentences and at points when we believe the speaker may have finished what they are saying.

The researchers plan to carry on their investigation; in particular, they would like to look at the participants’ answers in more detail.

This study only looked at the length of their answers, but it would be interesting to see how blink duration impacted other aspects of the answer, such as the level of detail, speech rate, and the number of hesitations.

It seems that this apparently simple physiological response might take a great deal of unraveling.

The work of a psychologist can range from counseling individuals with anxiety to advising companies on how to build better teams.

The mind is highly complex, and conditions that relate to it can be hard to treat.

Thought processes, emotions, memories, dreams, perceptions, and so on cannot be seen physically, like a skin rash or heart defect.

While physical signs of some mental health issues can be observed, such as the plaques that develop with Alzheimer’s disease, many theories of psychology are based on observation of human behavior.

A practicing psychologist will meet with patients, carry out assessments to find out what their concerns are and what is causing any difficulties, and recommend or provide treatment, for example, through counselling and psychotherapy.

Psychologists may have other roles, too. They may carry out studies to advise health authorities and other bodies on social and other strategies, assess children who find it difficult to learn in school, give workshops on how to prevent bullying, work with recruitment teams in companies, and much more.

There are different types of psychology that serve different purposes. There is no fixed way of classifying them, but here are some common types.

Clinical psychology

Clinical psychology integrates science, theory, and practice in order to understand, predict and relieve problems with adjustment, disability, and discomfort. It promotes adaption, adjustment, and personal development.

A clinical psychologist concentrates on the intellectual, emotional, biological, psychological, social, and behavioral aspects of human performance throughout a person’s life, across varying cultures and socioeconomic levels.

Clinical psychology can help us to understand, prevent, and alleviate psychologically-caused distress or dysfunction, and promote an individual’s well-being and personal development.

Psychological assessment and psychotherapy are central to the practice of clinical psychology, but clinical psychologists are often also involved in research, training, forensic testimony, and other areas.

Cognitive psychology

Cognitive psychology investigates internal mental processes, such as problem solving, memory, learning, and language. It looks at how people think, perceive, communicate, remember, and learn. It is closely related to neuroscience, philosophy, and linguistics.

Cognitive psychologists look at how people acquire, process, and store information.

Practical applications include how to improve memory, increase the accuracy of decision-making, or how to set up educational programs to boost learning.

Developmental psychology

This is the scientific study of systematic psychological changes that a person experiences over the life span, often referred to as human development.

It focuses not only on infants and young children but also teenagers, adults, and older people.

Factors include motor skills, problem solving, moral understanding, acquiring language, emotions, personality, self-concept, and identity formation.

It also looks at innate mental structures against learning through experience, or how a person’s characteristics interact with environmental factors and how this impacts development.

Developmental psychology overlaps with fields such as linguistics.

Evolutionary psychology

Evolutionary psychology looks at how human behavior, for example language, has been affected by psychological adjustments during evolution.

An evolutionary psychologist believes that many human psychological traits are adaptive in that they have enabled us to survive over thousands of years.

Forensic psychology

Forensic psychology involves applying psychology to criminal investigation and the law.

A forensic psychologist practices psychology as a science within the criminal justice system and civil courts.

It involves assessing the psychological factors that might influence a case or behavior and presenting the findings in court.

Health psychology

Health psychology is also called behavioral medicine or medical psychology.

It observes how behavior, biology, and social context influence illness and health.

A physician often looks first at the biological causes of a disease, but a health psychologist will focus on the whole person and what influences their health status. This may include their socioeconomic status, education, and background, and behaviors that may have an impact on the disease, such as compliance with instructions and medication.

Health psychologists usually work alongside other medical professionals in clinical settings.

Neuropsychology

Neuropsychology looks at the structure and function of the brain in relation to behaviors and psychological processes. A neuropsychology may be involved if a condition involves lesions in the brain, and assessments that involve recording electrical activity in the brain.

A neuropsychological evaluation is used to determine whether a person is likely to experience behavioral problems following suspected or diagnosed brain injury, such as a stroke.

The results can enable a doctor to provide treatment that may help the individual achieve possible improvements in cognitive damage that has occurred.

Occupational psychology

Occupational or organizational psychologists are involved in assessing and making recommendations about the performance of people at work and in training.

They help companies to find more effective ways to function, and to understand how people and groups behave at work.

This information can help improve effectiveness, efficiency, job satisfaction, and employee retention.

Social psychology

Social psychology uses scientific methods to understand how social influences impact human behavior. It seeks to explain how feelings, behavior, and thoughts are influenced by the actual, imagined or implied presence of other people.

A social psychologist looks at group behavior, social perception, non-verbal behavior, conformity, aggression, prejudice, and leadership. Social perception and social interaction are seen as key to understanding social behavior.

Other branches include military, consumer, educational, cross-cultural, and environmental psychology. The number of branches continues to grow.

In a philosophical context, psychology was around thousands of years ago in ancient Greece, Egypt, India, Persia, and China.

In 387 BCE, Plato suggested that the brain is where mental processes take place, and in 335 BCE Aristotle suggested that it was the heart.

Avicenna, the famous Muslim doctor, born in 980 AD, studied and treated epilepsy, nightmares, and poor memory. The first hospitals treating psychiatric conditions were said to have been set up by Islamic doctors in medieval times.

In 1774, Franz Mesmer proposed that hypnosis, or “mesmerism,” might help cure some types of mental illness.

In 1793, Philippe Pinel released the first patients with mental health problems from confinement in a move that signalled a move toward more humane treatment.

In 1879, Wilhelm Wundt, Germany, founded psychology as an independent experimental field of study. He set up the first laboratory that carried out psychological research exclusively at Leipzig University. Wundt is known today as the father of psychology.

In 1890, an American philosopher, William James, published a book entitled Principles of Psychology. It was discussed by psychologists worldwide for many decades. In the same year, New York State passed the State Care Act, in which people with mental health problems were to leave poor houses and enter the hospital for treatment.

In 1890, the American Psychological Association (APA) was founded, under the leadership of G. Stanley Hall.

Hermann Abbingaus, who lived from 1850 1909, and worked at the University of Berlin, was the first psychologist to study memory extensively.

Ivan Pavlov, who lived from 1849 to 1936, carried out the famous experiment which showed that dogs salivated when they expected food, introducing the concept of “conditioning.”

The Austrian Sigmund Freud, who lived from 1856 to 1939, introduced the field of psychoanalysis, a type of psychotherapy. He used interpretive methods, introspection, and clinical observations to gain understanding of the mind.

He focused on resolving unconscious conflict, mental distress, and psychopathology. Freud argued that the unconscious was responsible for most of people’s thoughts and behavior, and for mental health problems.

E. B Titchener, an American, strongly believed in structuralism, which focuses on the question: “What is consciousness?”

William James and John Dewey were strong believers in functionalism, which addressed the “What is consciousness for?”

The debate between the functionalists and structuralists led to a rapid growth in interest in psychology in the United States and elsewhere, and the establishment of the first psychology laboratory in the U.S., at Johns Hopkins University.

Behaviorism

In 1913 an American psychologist, John B. Watson, founded a new movement that changed the focus of psychology.

Behavior, he argued, is not the result of internal mental processes, but the result of how we respond to the environment.

Behaviorism focused on how people learn new behavior from the environment.

Humanism

Humanists viewed behaviorism and psychoanalytic theory as too dehumanizing.

Rather than being victims of the environment or the unconscious, they proposed that humans are innately good and that our own mental processes played an active role in our behavior.

The humanist movement puts high value on the emotions, free will, and a subjective view of experience.

Cognitive theory

Introduced in the 1970s, this is seen as the most recent school of thought in psychology.

Cognitive theorists believe that we take in information from our environment through our senses and then process the data mentally by organizing it, manipulating it, remembering it, and relating it to information we have already stored.

Cognitive theory is applied to language, memory, learning, perceptual systems, mental disorders, and dreams.

Today

Nowadays, psychologists study all these approaches and choose what appears to be best from each approach for a particular situation.

According to the American Psychological Association (APA), in the U.S., a pschologist can become licensed to practice with a doctoral degree in the field of psychology from an accredited university. In addition, each state has requirements for licensure.