• Psychologist John Broadus Watson, 1878
  

In October 1920 Johns Hopkins University asked Watson to leave his faculty position because of publicity surrounding the affair he was having with his graduate student assistant Rosalie Rayner.

Watson's affair had become front page news, during divorce proceedings, in the Baltimore newspapers. Mary Ickes Watson, his wife, had feigned illness during a dinner party involving the Rayner and Ickes families so that she could have unfettered access to Rayner's bedroom. She discovered love letters Watson had written to Rayner. She had hoped that by Watson knowing of this discovery, he would leave Rayner.

After the divorce was finalized, Watson and Rayner married in 1921. They remained together until her death in 1935.

In 1913, Watson published the article "Psychology as the Behaviourist Views It" — sometimes called "The Behaviorist Manifesto". In this article, Watson outlined the major features of his new philosophy of psychology, called "behaviorism". The first paragraph of the article concisely described Watson's behaviorist position:

Psychology as the behaviorist views it is a purely objective experimental branch of natural science. Its theoretical goal is the prediction and control of behavior. Introspection forms no essential part of its methods, nor is the scientific value of its data dependent upon the readiness with which they lend themselves to interpretation in terms of consciousness. The behaviorist, in his efforts to get a unitary scheme of animal response, recognizes no dividing line between man and brute. The behavior of man, with all of its refinement and complexity, forms only a part of the behaviorist's total scheme of investigation.

In 1913, Watson viewed Ivan Pavlov's conditioned reflex as primarily a physiological mechanism controlling glandular secretions. He had already rejected Edward L. Thorndike's "Law of Effect" (a precursor to B.F. Skinner's principle of reinforcement) due to what Watson believed were unnecessary subjective elements. It was not until 1916 that Watson would recognize the more general significance of Pavlov's formulation and make it the subject of his presidential address to the American Psychological Association. The article is also notable for its strong defense of the objective scientific status of applied psychology, which at the time was considered to be much inferior to the established structuralist experimental psychology.

With his "behaviorism", Watson put the emphasis on external behavior of people and their reactions on given situations, rather than the internal, mental state of those people. In his opinion, the analysis of behaviors and reactions was the only objective method to get insight in the human actions. This outlook, combined with the complementary ideas of determinism, evolutionary continuism, and empiricism has contributed to what is now called radical behaviorism. It was this new outlook that Watson claimed would lead psychology into a new era. He claimed that before Wundt there was no psychology, and that after Wundt there was only confusion and anarchy. It was Watson's new behaviorism that would pave the way for further advancements in psychology.

Watson's behaviorism rejected the studying of consciousness. He was convinced that it could not be studied, and that past attempts to do so have only been hindering the advancement of psychological theories. He felt that introspection was faulty at best and awarded researchers nothing but more issues. He pushed for psychology to no longer be considered the science of the "mind". Instead, he stated that psychology should focus on the "behavior" of the individual, not their consciousness.

Give me a dozen healthy infants, well - formed, and my own specified world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select – doctor, lawyer, artist, merchant - chief and, yes, even beggar - man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors. I am going beyond my facts and I admit it, but so have the advocates of the contrary and they have been doing it for many thousands of years.

The quotation often appears with the last sentence omitted, making Watson's position appear more radical than it actually was. Watson had, in fact, done extensive ethological studies of the instinctive behavior of animals early in his career, particularly sea birds. Nevertheless, Watson strongly sided with nurture in the nature versus nurture discussion.

The 20th century marked the formation of qualitative distinctions between children and adults. Watson wrote the book Psychological Care of Infant and Child in 1928, with help from his mistress, turned wife, Rosalie Rayner. Critics then determined that the ideas mainly stemmed from Watson’s beliefs because Rosalie later entitled a self - penned article I am a Mother of Behaviorist Sons. In the book, Watson explained that behaviorists were starting to believe psychological care and analysis was required for infants and children. All of Watson’s exclamations were due to his belief that children should be treated as a young adult. In his book, he warns against the inevitable dangers of a mother providing too much love and affection. Watson explains that love, along with everything else as the behaviorist saw the world, is conditioned. Watson supports his warnings by mentioning invalidism, saying that society does not overly comfort children as they become young adults in the real world, so parents should not set up these unrealistic expectations. Writer Suzanne Houk, Psychological Care of Infant and Child: A Reflection of its Author and his Times, critiques Watson’s views, analyzing his hope for a businesslike and casual relationship between a mother and her child. Watson also warned to avoid letting the infant sit on a parents’ lap.

He deemed his slogan to be not more babies but better brought up babies. Watson argued for the nurture side of the nature - nurture debate, claiming that the world would benefit from extinguishing pregnancies for twenty years while enough data was gathered to ensure an efficient child rearing process. Further emphasizing nurture, Watson said that nothing is instinctual; rather everything is built into a child through the interaction with their environment. Parents therefore hold complete responsibility since they choose what environment to allow their child to develop in. Laura E. Berk, author of Infants and Children: Prenatal Through Middle Childhood, examined the roots of the beliefs Watson came to honor. Berk says that the experiment with Little Albert inspired Watson’s emphasis on environmental factors. Little Albert did not fear the rat and white rabbit until he was conditioned to do so. From this experiment, Watson concluded that parents can shape a child’s behavior and development simply by a scheming control of all stimulus - response associations.

Although he wrote extensively on child rearing in many popular magazines and in a book, Psychological Care of Infant and Child (1928), Watson later regretted having written in the area, saying that "he did not know enough" to do a good job. Watson's advice to treat children with respect, but with relative emotional detachment, has been strongly criticized. J.M. O’Donnell wrote The Origins of Behaviorism, where he deemed Watson’s views as radical calculations. O’Donnell’s discontent stemmed partly from Watsons’ description of a happy child, including that the child only cry when in physical pain, can occupy himself through his problem solving abilities, and that the child stray from asking questions. Behavior analysis of child development as a field is largely thought to have begun with the writings of Watson.

Other critics were more wary of Watson’s new interest and success in child psychology. R. Dale Nance worried that Watson’s personal indiscretions and difficult upbringings could have affected his views in his book. He was raised on a poor farm in South Carolina and had various family troubles, including abandonment by his father. Suzanne Houk shared similar concerns. She mentions in her article that Watson only shifted his focus to child rearing when he was fired from Johns Hopkins University due to his affair with Rosalie Rayner.

Watson researched many topics in his career, but child rearing became his most prized interest. His book was extremely popular and many critics were surprised to see his contemporaries come to accept his views. The book sold 100,000 copies after just a few months of release.

Watson’s emphasis on child development was becoming a new phenomenon and influenced some of his successors, but there were psychologists before him that delved into the field as well. G. Stanley Hall became very well known for his 1904 book Adolescence. G. Stanley Hall’s beliefs differed from behaviorist Watson, believing that heredity and genetically predetermined factors shaped most of one’s behavior, especially during childhood. His most famous concept, Storm and Stress Theory, normalized adolescents’ tendency to act out with conflicting mood swings. Whether Watson’s views were controversially radical or not, they garnered a lot of attention and were accepted as valuable in his time.

One might consider the experiment Watson and his assistant Rosalie Rayner carried out to be one of the most controversial in psychology in 1920. It has become immortalized in introductory psychology textbooks as the Little Albert experiment. The goal of the experiment was to show how principles of, at the time recently discovered, classical conditioning could be applied to condition fear of a white rat into "Little Albert", an 11 month old boy. Watson and Rayner conditioned "Little Albert" by clanging an iron rod when a white rat was presented. First, they presented to the boy a white rat and observed that he was not afraid of the rodent. Second, they presented him with a white rat and then clanged an iron rod. "Little Albert" responded by crying. This second presentation was repeated several times. Finally, Watson and Rayner presented the white rat by itself and the boy showed fear. This study demonstrated how emotions could become conditioned responses. As the story of "Little Albert" has made the rounds, inaccuracies and inconsistencies have crept in, some of them even due to Watson himself. An ethical problem of this study is that Watson and Rayner did not uncondition "Little Albert". In 2009, Beck, Levinson, and Irons sought out "Little Albert" to see how Watson's study affected his life. They found that he had died from hydrocephalus at the age of 6. Thus, we cannot conclude to what extent this study had an effect on "Little Albert's" life.

Thanks to contacts provided by an academic colleague, E.B. Titchener, Watson subsequently began working for U.S. advertising agency J. Walter Thompson. He learned the advertising business' many facets at ground level, including a stint working as a shoe salesman in an upscale department store. Despite this modest start, in less than two years Watson had risen to a vice - presidency at Thompson. His executive's salary, plus bonuses from various successful ad campaigns, resulted in an income many times higher than his academic salary. Watson headed a number of high profile advertising campaigns, particularly for Ponds cold cream and other personal care products. In addition, he is credited with popularizing the "coffee break" during an ad campaign for Maxwell House coffee. He has been widely but erroneously credited with re-introducing the "testimonial" advertisement after the tool had fallen out of favor (due to its association with ineffective and dangerous patent medicines). However, testimonial advertisements had been in use for years before Watson entered advertising. Watson stated that he was not making original contributions, but was just doing what was normal practice in advertising. Watson stopped writing for popular audiences in 1936, and retired from advertising at about age 65.

Watson was the maternal grandfather of actress Mariette Hartley, who suffered with psychological issues she attributed to her being raised with her grandfather's theories.

Rosalie Rayner died in 1935 at age 36. Watson lived on their farm until his death in 1958 at age 80. Right before his death in 1957, he received a Gold Medal from the American Psychological Association for his contributions to psychology.

Historian John Burnham interviewed Watson late in life, and portrayed him as a man of (still) strong opinions and some bitterness towards his detractors. Except for a set of reprints of his academic works, Watson burned his very large collection of letters and personal papers, thus depriving historians of a valuable resource for understanding the early history of behaviorism and of Watson himself.