The purpose of this study was to isolate some independent variables that may be directly related to beginning reading ability. The study was conducted in two phases: the piloting and revision of four perceptual tests involving the ability to manipulate sequential stimuli within or between the visual and auditory modalities; and the administration of the revised, perceptual tests to two groups of third-graders. The pilot tests were administered to 77 children within a single elementary school. The revised tests were administered to 50 children average or above in reading achievement and 50 children retarded more than one year in reading. It was concluded from the results that only one of the perceptual tests differentiated between the retarded and average or above readers. The average or above readers performed significantly better than the retarded readers on the revised, visual intrasensory test. It was also found that girls performed significantly better than the boys on the revised, auditory intrasensory test. (Author/TS)