ness of pictorial and verbal information in printed instructional materials for deaf subjects. Four types of instructional formats were pre-pared, varying in proportion of pictorial and verbal information: (a) all pictorial; (b) pre-dominantly pictorial, with some ancillary verbal information; (c) all verbal; and (d) pre-dominantly verbal, with some ancillary pictorial information. Each format was given to a separate group of deaf college students. The instructional materials described sequences of operational procedures to be carried out by subjects on a complex control-display apparatus. Performance was measured by task completion time and error rate. Results