Term originally used by Gertrude Schmeidler (1943) to describe a subject who rejects the possibility that extrasensory perception could occur under the conditions of the given experimental situation; this somewhat narrow meaning has been extended to refer also, or alternatively, to persons who do not believe in the existence of ESP in general (that is, under any conditions!), or even to persons who obtain low scores on various so-called “projective,” “scalar” or “checklist” measures of belief in (and/or experience of) different sorts of putative psi phenomena. Compare Sheep. See Sheep-Goat Effect.