The terms alien abduction or abduction phenomenon describe "subjectively real memories of being taken secretly against one's will by apparently nonhuman entities and subjected to complex physical and psychological procedures". People claiming to have been abducted are usually called "abductees" or "experiencers". Typical claims involve being subjected to forced medical examinations that emphasize abductee reproductive systems. Abductees sometimes claim to have been warned against environmental abuse and the dangers of nuclear weapons.
Due to a lack of objective physical evidence, most scientists and mental health professionals dismiss the phenomenon as "deception, suggestibility (fantasy-proneness, hypnotizability, false memory syndrome), personality, sleep paralysis, psychopathology, psychodynamics [and] environmental factors". Skeptic Robert Sheaffer sees similarity between the aliens depicted in science fiction films, in particular, Invaders From Mars, and some of those reported to have actually abducted people.
The first alleged alien abduction claim to be widely publicized was the Betty and Barney Hill abduction in 1961. Reports of the abduction phenomenon have been made around the world, but are most common in English speaking countries, especially the United States. The contents of the abduction narrative often seem to vary with the home culture of the alleged abductee.