Jacobs is a prominent figure in ufology and the study of the alien abduction phenomenon, including the use of hypnosis on subjects claiming to be abductees.

In recent years, Jacobs has publicly argued that the evidence from his research, which sometimes includes utilizing hypnotic regression with alleged alien abductees along with traditional interview techniques, purports that alien-human hybrids were engaged in a covert program of infiltration into human society with possibly the final goal of taking over Earth.

[17] Clancy has highlighted problems associated with abduction research, such as faulty memory retrieval when hypnotists "lead" the patient, and a failure to consider sleep paralysis as an explanation.

[18] Gardner explains: "Although Jacobs has had no training in psychology, psychiatry, or hypnotherapy, he uses hypnotism to induce his patients (now more than seven hundred) to develop strong memories of horrendous abductions even though many patients had no such memories until hypnotized (Though many abductees have claimed to remember bits and pieces of the abduction experience without the implementation of hypnotherapy).

"[19] Jacobs has argued that Clancy's methodology was flawed,[20] stating that in numerous cases people report they were abducted when fully awake and conscious, and that therefore sleep paralysis is not a tenable hypothesis.