The earliest known writings about psychological topics date to 1550 B.C.E. It was then that the Ancient Egyptians wrote about several psychological conditions – depression and schizophrenia among them – in the Ebers Papyrus.
Granted, the Egyptians believed that these psychological conditions had supernatural causes, so the Ebers Papyrus wasn’t exactly a science-based and reliable diagnostic manual like the DSM-V is today. However, the very fact that the Egyptians understood that difficulties of the mind existed and sought to explain why they occurred laid the groundwork for the development of psychology over the millennia.
Considering that the history of psychology extends back over 3,500 years, selecting just ten key moments in this discipline is a tall task. One could easily select dozens of turning points in psychology that have molded it into the science we know today. With that said, the following ten events should be considered as being crucial moments in the field of psychology.
Hippocrates Argues That the Brain, Not the Heart, is Responsible for Psychological Processes
In the fifth century B.C.E., Hippocrates publicly rejected the notion that spirits caused mental and physical disorders and instead proposed that natural elements were responsible. In particular, he agreed with Plato’s assertion (made in 387 B.C.E.) that the brain was at the center of mental processes and not the heart, as Aristotle postulated in 335 B.C.E.
In The Art of Healing, Hippocrates outlined the symptoms of common abnormal behaviors, including depression, paranoia, and mania. In On the Nature of Man, he explored the four humours (blood, yellow bile, black bile, and phlegm) and described how an imbalance between them led to personality disorders.
For example, Hippocrates believed that if one had too much yellow bile, one would have a propensity for anger and that too much black bile would result in one being melancholic.
Why this event is important: Hippocrates laid the groundwork for identifying and describing mental disorders in a scientific, rather than a supernatural, manner. His theories on the four humours formed the basis of research into temperament, personality, and motivation for centuries to come.
Galen Classifies Personality Types
Where Hippocrates’ theory of the four humours laid the groundwork for exploring human personality, it was Galen, who lived between 130-200 A.D., that took that work a step further.
In his book Pericraison, De temperamentis, Galen associated the four humour types with both temperaments and personality types. Like Hippocrates, Galen believed that an imbalance of the humours resulted in the expression of specific personality traits.
For example, Galen wrote (as did Hippocrates) that too much black bile resulted in a person having a melancholy about them. However, Galen extended that theory to suggest that the personality traits associated with a melancholy temperament included being sentimental and introspective.
As another example, Galen proposed that an excess of the blood humour resulted in a sanguine temperament that was expressed in personality traits that included hopefulness and courage.
Galen also expressed the idea that one cannot work through their faults unless they do so with a therapist. As a result, he is the first known person to describe the therapeutic relationship.
Why this event is important: Galen’s work in examining human personality was so influential that it remained the standard method of personality research for over 1,000 years.
The First Mental Hospital Opens in London
In the early 14th century, Bedlam Hospital began admitting patients for treatment of mental disorders. The hospital, which was acquired by the City of London in 1547, was in virtually continuous operation until 1948.
Why this event is important: The opening of a mental hospital signified a shift in thinking about the mentally ill. Though the history of Bedlam Hospital is not all great (there was a period of time in which patrons could pay to tour the hospital and observe the patients as a form of entertainment), it did mark the beginning of the use of hospitalization and rehabilitation to treat mental disorders with the goal of discharging the patient back into society.
The First Use of the Word “Psychology”
In approximately 1524, Marko Marulić, a poet and humanist from Croatia, published Psichiologia de ratione animae humanae. The word psichiologia in the text’s title is the first such instance that the term psychology was used. Sixty-six years later, Rudolph Goclenius wrote Lexicon Philosophicum, in which the word psychology was defined.
It wasn’t until 1734 when Christian Wolff published Psychologia empirica and Psychologia rationalis that the term psychology became a popularized word.
Why this event is important: Giving a name to the field of psychology enabled it to grow separately from its roots in medicine, philosophy, and other schools of study and thought. Once named, psychology could develop as a legitimate field of study and the evolution of psychology as a science began.
The Phineas Gage Accident
In September 1848, Phineas Gage, a railroad worker in Vermont, was injured when a premature explosion sent a 3-foot-long metal rod through his left cheek and out the top of his skull. Gage miraculously survived, and though he lost some function on the left side of his face and was blind in his left eye, he had no lingering physical or intellectual difficulties.
However, Gage’s personality completely changed. The man who was once revered by his employer as the finest of foremen could no longer follow a plan, had little regard for other people and was described by loved ones as “no longer Gage.”
Why this event is important: These observations, made by Gage’s Doctor, John Martyn Harlow, revealed the connection between the brain and personality. What’s more, the accident shed light on the compartmentalization of the brain and led to the discovery that personality is centered in the frontal lobe.
The World’s First Psychological Laboratory Opens
In 1879, over 350 years after the first known usage of the term “psychology,” Wilhelm Wundt founded the world’s first laboratory specifically for the study of psychology.
The laboratory was located in Leipzig, Germany, at the University of Leipzig. Wundt sought to apply an experimental method to the study of psychology, specifically as it pertained to the exploration of human behavior, emotions, and cognition.
In particular, Wundt and his proteges wanted to remove introspection from the process of studying human behavior and focused instead on using experimental stimuli that could be controlled, the results of which could be recorded and later shown to be replicable.
Why this event is important: Wundt’s work in the University of Leipzig psychology laboratory established psychology as a science separate from philosophy and biology. Furthermore, several of Wundt’s students went on to become highly influential psychologists in their own right, including G. Stanley Hall, who established the first psychology lab in the United States and is considered the father of both educational psychology and child psychology.
William James Publishes The Principles of Psychology
In 1890, a full ten years after starting work on it, William James, one of the most prominent early American psychologists, published The Principles of Psychology.
The massive text was understood at the time to be ground-breaking in the manner in which it described the still relatively new field of psychology. In it, James managed to bring current understandings of mental science together with biological disciplines, which allowed him to explain how physical processes can influence mental processes.
Today, it is recognized as one of the seminal works in the field, having established a description and understanding of functional psychology.
Why this event is important: The Principles of Psychology gave credence to psychology’s credibility as a science. It also described James’ theory of emotion (known as the James-Lange Theory), which postulated that emotions are the result of a physical response to a stimulus.
Ivan Pavlov Introduces the World to Classical Conditioning
In the late 19th century, Ivan Pavlov, a Russian physiologist, studied the salivation of dogs in response to the presentation of food. Pavlov predicted that dogs would begin to salivate in response to the presentation of food, but he accidentally discovered something much more complex.
Pavlov noticed that the dogs began to salivate well before the food was presented to them. In fact, the salivary response began when they heard the footsteps of his assistant in the hallway, who was responsible for feeding the dogs. He then began to pair other stimuli (i.e., a bell) with the presentation of food and learned that when the bell was presented alone, the salivary response could be triggered.
Why this event is important: Pavlov’s work was the beginnings of classical conditioning, which posits that a neutral stimulus (i.e., a bell) paired with an unconditioned stimulus (i.e., food) could come to elicit the same response (i.e., salivation) through conditioning. This research influenced the development of the psychological school of behaviorism and the work of John B. Watson (who used these techniques to condition fear in a child).
Sigmund Freud Lays the Foundation for Psychoanalysis
While Ivan Pavlov was studying his dogs, Sigmund Freud was turning inward and analyzing his own dreams, a process he first undertook in 1895.
A year later, Freud used the term “psychoanalysis” for the first time. In the ensuing years, he would perfect his psychoanalytic theory, which held that unconscious thoughts, feelings, memories, and emotions were the root of mental difficulties. In particular, he was interested in how events during childhood influenced the mental functioning of people in adulthood.
One of the critical components of Freud’s work was dream analysis. His most well-known and influential book, The Interpretation of Dreams, centered on this very subject. In it, Freud postulated that dreams included manifest content, or the subject matter about which the individual dreamt, and the latent content, or the true meaning of the dream’s events.
Why this event is important: Freud is one of the most important figures in the development of psychology in the 20th Century. What started as self-evaluation and dream interpretation led to his theory of psychosexual development, the exploration of human personality in the context of the Id, Ego, and Superego, and the development of therapeutic techniques (i.e., talk therapy, free association, and transference) that are still in use today.
The Wechsler-Bellevue Intelligence Scale is Developed
In 1939, Dr. David Wechsler, who was a clinical psychologist at Bellevue Hospital, published Form One of the Wechsler-Bellevue Intelligence Scale. Wechsler developed the test to measure the intellectual abilities of adults because up to that point, the only assessments available to test adult intelligence were those adapted from child intelligence tests and therefore had very little face validity for measuring adult intelligence.
Wechsler’s definition of intelligence revolved around one’s ability to adapt to novel situations and problem solve. By making the measurement of intelligence based on one’s performance, Wechsler was able to quantify intelligence in a way that had not previously been possible. As a result, the Wechsler-Bellevue became the standard-bearer of intelligence tests and has since grown to specialized scales for adults, children between the ages of 6 and 16, and children between 4 and 6 ½ years of age.
Why this event is important: Wechsler’s test, like the Stanford-Binet before it, was instrumental in conceptualizing intelligence on a multidimensional construct. That is, it defined intelligence not as a single characteristic (i.e., “smarts”) but instead as many different types of intellect that comprise one’s intelligence. Today, the Wechsler battery of intelligence tests are still the most used psychological assessments in the world.
Bonus: The Diagnostic and Statistical Manual of Mental Disorders is Published
Now in its fifth edition, the DSM was first published in 1952 as a manual for classifying mental illnesses. The DSM was heavily influenced by the International Classification of Diseases-6 (ICD-6) and the terminology developed by the U.S. Department of Veterans Affairs, which sought to create standardized nomenclature to describe mental health problems that were prevalent among service members after World War II.
This classification system helped standardize the diagnostic procedure for dozens of mental disorders and ensured that people seeking help for mental illness would receive the same kind of treatment regardless of their location, social standing, ability to pay, and so forth. Likewise, the DSM system allowed therapists and others in the field of psychology and psychiatry to develop mental health assessments and treatments that furthered their ability to provide care.
Why this event is important: Though the DSM system has its faults and detractors, it has been highly influential in making psychological assessment easier and more accurate.
BA Social Studies Education | University of Wyoming
MS Counseling | University of Wyoming
BS Information Technology | University of Massachusetts