The word paranormal is a catch-all term used for supernatural phenomena, particularly such things as ghosts, psychic ability, and miracles, the cause for which is beyond the range of normal perception and scientific analysis. Paranormal researchers sometimes refer to paranormal activity as PSI phenomena.

To clarify further, because paranormal phenomena is supernatural in origin, its very nature defies scientific analysis. For example psychic ability manifests itself directly as knowledge within the mind, and although we might be able to verify that the knowledge is accurate, there is no way to scientifically determine how it got there. There are similarly difficult challenges in the analysis of phenomena connected to religious belief. According to religious mythology, demons, angels and other dieties exist in a realm that is beyond the reach of scientific study.

Because UFOs are material objects that can be detected by such things as cameras and radar, if one were secured, there is the possibility that it could be studied under all the conditions required for valid scientific analysis. Therefore UFOs are not paranormal in nature. However sometimes PSI phenomena are associated with UFO reports, leading ufologists like J. Randall Murphy to speculate that certain types of PSI phenomena might be associated with alien technology (ATECH), including cloaking devices, antigravity generators, sonic projectors, electromagnetic fields, holographic projectors, and biometric scanners.

PSI phenomena resulting from ATECH could be partially accidental. For example hallucination inducing magnetic fields might be a byproduct of UFO propulsion systems. On the other hand ATECH could also be useful in clandestine studies of human behavior. On a more conspiratorial level by manifesting the supernatural events that gave rise to major religions, authors like William Bramley have suggested that ATECH might have been used to manipulate the course of global social evolution.