Portable digital voice recorders are currently the technology of choice for some EVP investigators. Since some of these devices are very susceptible to Radio Frequency (RF) contamination, EVP enthusiasts sometimes try to record EVP in RF- and sound-screened rooms. Some EVP enthusiasts describe hearing the words in EVP as an ability, much like learning a new language. Skeptics suggest that the claimed instances may be misinterpretations of natural phenomena, inadvertent influence of the electronic equipment by researchers, or deliberate influencing of the researchers and the equipment by third parties. EVP and ITC are seldom researched within the scientific community, so most research in the field is carried out by amateur researchers who lack training and resources to conduct scientific research, and who are motivated by subjective notions. Explanations and origins Paranormal claims for the origin of EVP include living humans imprinting thoughts directly on an electronic medium through psychokinesis and communication by discarnate entities such as spirits, nature energies, beings from other dimensions, or extraterrestrials. Paranormal explanations for EVP generally assume production of EVP by a communicating intelligence through means other than the typical functioning of communication technologies. Natural explanations for reported instances of EVP tend to dispute this assumption explicitly and provide explanations which do not require novel mechanisms that are not based on recognized scientific phenomena. One study, by psychologist Imants Barušs, was unable to replicate suggested paranormal origins for EVP recorded under controlled conditions. Brian Regal in Pseudoscience: A Critical Encyclopedia (2009) has written "A case can be made for the idea that many EVPs are artifacts of the recording process itself with which the operators are unfamiliar. The majority of EVPs have alternative, nonspiritual sources; anomalous ones have no clear proof they are of spiritual origin." Natural explanations There are a number of simple scientific explanations that can account for why some listeners to the static on audio devices may believe they hear voices, including radio interference and the tendency of the human brain to recognize patterns in random stimuli. Some recordings may be hoaxes created by frauds or pranksters. Psychology and perception Auditory pareidolia is a situation created when the brain incorrectly interprets random patterns as being familiar patterns. In the case of EVP it could result in an observer interpreting random noise on an audio recording as being the familiar sound of a human voice. The propensity for an apparent voice heard in white