This research investigated temporal ordering acuity in children, or the ability to perceive the first of an ordered pair of lights, or of a combined light and tone, when the interstimulus time interval within each pair became increasingly short in duration. Two group-related comparisons were made: (1) differences between slow-maturing and average kindergartners, and (2) differences between an educationally handicapped group deficient in language skills and two other groups, a normal third grade and a hyperactive EH group. In addition, task-wise correlations measured relationships of task performance within groups. Results indicated that significant differences were apparent in all tasks when the two kindergarten samples were compared; and that the slow EH group was significantly deficient in auditory and cross-modal tasks. Correlation measures suggested that: (1) Poor auditory processing and deficient intersensory functioning are correlated in slow-maturing kindergartners and the slow EH group; (2) Visual acuity is not necessarily affected by deficiencies in auditory or cross-modal areas; and (3) Auditory and visual acuity are similar kinds of capabilities for normal populations and for the hyperactive EH group who are adequate in language processing skills. The present experiment showed that a relationship exists between cognitive development and perceptual acuity in kindergarten. (Author/CK)