The incidence of persons possessing eidetic imagery was determined for normal adults, normal school children, familial retardates, and brain-injured retardates (total N = 270). Three methods of evaluation were used for all Ss: (1) the “standard” method, in which the S describes a complex scene after viewing it for 30 sec, (2) a task which requires superimposing the eidetic image of one stimulus upon a second stimulus, thus producing an unexpected third pattern; and (3) the Stromeyer and Psotka task of binocularly fusing two Julesz patterns, one of which is an eidetic image. The latter two methods were considered to be more objective than the first and less likely to incorrectly classify a person as an eidetiker. According to the first method, eidetikers were found only among the familial retardates (2 of 19 Ss); by the other two methods, none of the Ss possessed eidetic ability.