Autosuggestion is a psychological technique related to the placebo effect, developed by pharmacist Émile Coué at the beginning of the 20th century. It is a form of self-induced suggestion in which individuals guide their own thoughts, feelings, or behavior. The technique is often used in self-hypnosis.
Émile Coué identified two very different types of self-suggestion:
intentional, "reflective autosuggestion": made by deliberate and conscious effort, and
unintentional, "spontaneous auto-suggestion": which is a "natural phenomenon of our mental life ... which takes place without conscious effort [and has its effect] with an intensity proportional to the keenness of [our] attention".
In relation to Coué's group of "spontaneous auto-suggestions", his student Charles Baudouin (1920, p. 41) made three further useful distinctions, based upon the sources from which they came:
"Instances belonging to the representative domain (sensations, mental images, dreams, visions, memories, opinions, and all intellectual phenomena)."
"Instances belonging to the affective domain (joy or sorrow, emotions, sentiments, tendencies, passions)."
"Instances belonging to the active or motor domain (actions, volitions, desires, gestures, movements at the periphery or in the interior of the body, functional or organic modifications)."
Émile Coué, who had both B.A. and B.Sc. degrees before he was 21, graduated top of his class (with First Class Honours) with a degree in pharmacology from the prestigious Collège Sainte-Barbe in Paris in 1882. Having spent an additional six months as an intern at the Necker-Enfants Malades Hospital in Paris, he returned to Troyes, where he worked as an apothecary from 1882 to 1910.
In 1885, his investigations of hypnotism and the power of the imagination began with Ambroise-Auguste Liébeault and Hippolyte Bernheim, two leading exponents of "hypnosis", of Nancy, with whom he studied in 1885 and 1886 (having taken leave from his business in Troyes).