Alien Abduction Theories: A Scientific Search for Evidence

People who claim to have been abducted by aliens typically describe their abductors as little, gray humanoids with oversize heads, slanted eyes, two holes for a nose and a slit for a mouth. David Wall / Getty Images

Alien abduction stories have spread widely over the last hundred years, though a large proportion did not truly hit their stride until the 1961 Barney and Betty Hill abduction. After the Hill abduction, investigators collected more and more accounts, usually, though not always, elicited through hypnosis.

Some abductees report their abductions as warm, pleasant experiences with intense psychic contact. Other abductees have reported that aliens conducted scientific experiments or operations on their unwilling patients. How can these vastly different experiences be explained?


Long-term Tracking in Alien Abduction Stories

In most cases, witnesses told of seeing a UFO (now called UAPs) or even humanoid beings, then experienced either an altered state of consciousness or amnesia for a period of anywhere from a few minutes to a few hours. Some witnesses claimed repeated experiences that started when they were children.

The clear implication was that UFO beings (typically described in these instances as little, gray humanoids with oversize heads, slanted eyes, two holes for a nose and a slit for a mouth) had a long-term interest in certain human beings. Some abductees even reported that the abductors had put small implants — usually said to be tiny balls inserted through the nose and (apparently) into the brain via a long needle — inside their bodies.


In time, new and even more unsettling dimensions to the abduction experience came to light. Some female abductees reported sexual experiences followed by pregnancies that would be terminated in a follow-up abduction some months later. During later abductions, the UFO entities would show the women strange-looking children, apparently human-alien hybrids, whom they would sense were their own.

This phenomenon prompted a question that continues to perplex both ufologists and modern scientists alike: Why would an otherworldly entity take interest in some humans over others?


The Hypnosis Theory

Not surprisingly, scientific reports that offered alternative explanations for these experiences have been met with pushback from believers. Even some abduction researchers rejected them, preferring — in common with UFO skeptics — to believe "abductions" were fantasies generated by the process of hypnosis itself.

Contrary to popular understanding, hypnosis is no royal road to the truth. Hypnotic subjects are in a highly suggestible state and may seek to please the hypnotist. Thus, if the hypnotist asks leading questions, the subject could be led to provide the desired answers.


The link between false memories and hypnosis lies in the susceptibility of individuals under hypnosis to generate or accept memories that did not actually occur. Hypnosis can lead to the creation of vivid and convincing but inaccurate recollections. Purely imaginary events can seem real under hypnosis (confabulation), as testified to in the phenomenon of "past lives" recounted while in a hypnotic state.

Testing the Theory

To test the confabulation hypothesis, folklorist Thomas E. Bullard collected all available abduction accounts. He found that as many as 1/3 of the informants had full conscious recall of their experiences and had never resorted to hypnosis to elicit the details. These non-hypnotic reports proved identical in all significant particulars to those told under hypnosis.

Bullard also learned that the identity of the individual hypnotist made no difference. The stories remained consistent down to details that even those most familiar with the phenomenon had failed to notice.

In short, Bullard concluded, whatever its ultimate cause, the abduction phenomenon was not the product of hypnosis. "The skeptical argument needs rebuilding from the ground up," he wrote. However, some members of the scientific community still believe that false memories are one of the many reasons behind the alien abduction phenomenon.


Investigating Abduction Claims

Mental health experts and researchers have been exploring the abduction phenomenon for decades. In the early 1980s, a study involving psychological assessments of a limited set of abductees in New York suggested that they were grappling with post-traumatic stress disorder (PTSD). Other studies since then have come to similar conclusions.

In a 2022 study, researchers investigated the emotional responses of individuals who claimed to have experienced alien abductions, aiming to offer alternative explanations aside from severe psychopathology. The study involved 19 individuals who reported being abducted by aliens, compared to a control group of 32 participants.


Using various tests, including assessments of post-traumatic stress disorder(PTSD), suggestibility and dissociation, researchers found that the abductee group exhibited higher scores in PTSD and dissociation, while scoring lower in suggestibility. However, only the differences in suggestibility were statistically significant.

The study suggested that emotional reactions to memories of implausible experiences can mirror those of genuinely traumatic events, and dissociation might play a role in understanding some cases.


Trauma Responses and Alien Abductions

In an article published in the Journal of Experimental Psychopathology, psychologist Richard McNally and a team of Harvard researchers examined whether people who recall false traumatic events, like UFO abductions, display physiological responses akin to those who genuinely experienced trauma.

The investigation focused on individuals with obviously fictitious memories, particularly memories of alien abductions. Researchers crafted brief audio narratives based on the volunteers' abduction accounts to assess the responses of the small group of male and female subjects who agreed to participate in the study.


While the volunteers listened, researchers monitored indicators like heart rate, perspiration and facial muscle tension. Remarkably, these physiological measures surged as the abductees recollected their supposed experiences of being kidnapped by space aliens.

Abduction or Sleep Paralysis?

Ultimately, researchers chalked these recollections up to two possible reasons. One, the abductees had actually experienced alien encounters. Or two, they possessed a handful of "ingredients" that researchers had compiled to form "a recipe" for the type of person who is likely to experience an encounter or abduction.

These ingredients include:

  1. New Age beliefs (e.g., high scores on measures of magical ideation)
  2. episodes of isolated sleep paralysis accompanied by hypnopompic hallucinations
  3. hypnotic memory recovery sessions
  4. high scores on a measure of absorption
  5. familiarity with the cultural narrative of alien abduction.

But researchers were unsure if their recipe could also apply to people outside of the study who claim to have been abducted. Also, it was unclear whether an individual needed to possess all of the ingredients.

In other words, just because a person loves extraterrestrial movies or the "X-Files" and is easily influenced doesn't mean they're necessarily more — or less — likely to say that space aliens scooped them up for experiments in the middle of the night.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.