A concept in parapsychology that explained some significant scoring effects on ESP tests. In 1942, when parapsychology was still less than a decade old, Gertrude Schmeidler suggested that scoring could be affected by the subjects’ belief system. Schmeidler concluded that those who believed in the possibility of ESP (whom she labeled “sheep”) would score higher than those who did not believe in it (whom she labeled “goats”). The tests she gave bore out her hypothesis. Though the differences between the two groups were small, they were nevertheless statistically significant, and the concept has become an accepted truth in parapsychology.