This causes an alternation of the electric charge pattern on the film. After rigorous experimentations, no mysterious process has been discovered in relation to the Kirlian photography. More recent attempts at capturing auras include the Aura Imaging cameras and software introduced by Guy Coggins in 1992. Coggins claims that his software uses biofeedback data to color the picture of the subject. The technique has failed to yield reproducible results. Tests Tests of psychic abilities to observe alleged aura emanations have repeatedly been met with failure. One test involved placing people in a dark room and asking the psychic to state how many auras she could observe. Only chance results were obtained. Recognition of auras has occasionally been tested on television. One test involved an aura reader standing on one side of a room with an opaque partition separating her from a number of slots which might contain either actual people or mannequins. The aura reader failed to identify the slots containing people, incorrectly stating that all contained people. In another televised test another aura reader was placed before a partition where five people were standing. He claimed that he could see their auras from behind the partition. As each person moved out, the reader was asked to identify where that person was standing behind the slot. He identified two out of five correctly. Attempts to prove the existence of auras scientifically have repeatedly met with failure; for example people are unable to see auras in complete darkness, and auras have never been successfully used to identify people when their identifying features are otherwise obscured in controlled tests. A 1999 study concluded that conventional sensory cues such as radiated body heat might be mistaken for evidence of a metaphysical phenomenon. Scientific explanation Psychologist Andrew Neher has written that "there is no good evidence to support the notion that auras are, in any way, psychic in origin." Studies in laboratory conditions have demonstrated that auras are instead best explained as visual illusions known as afterimages. Neurologists contend that people may perceive auras because of effects within the brain: epilepsy, migraines, or the influence of psychedelic drugs such as LSD. It has been suggested that auras may result from synaesthesia. However, a 2012 study discovered no link between auras and synaesthesia, concluding "the discrepancies found suggest that both phenomena are phenomenological and behaviourally dissimilar." Clinical neurologist Steven Novella has written: "Given the weight