Seven studies were conducted to investigate the interactions between imagery-ability and experimental treatments that parallel instructional procedures. The general orientation of the studies was to extend the concepts of imaginal and verbal coding systems to include individual differences in symbolic habits. Thus all the studies took into account the learner's ability to use the imaginal strategy, which was called imagery-ability, as the primary individual difference variable. The results of the studies suggest that imaginal processing is more effective for the learning of concrete words and verbal processing is more effective for the learning of abstract words. Another conclusion from these investigations is that imagery-ability reflects the ability of the learner to process the information by verbal or by imaginal strategies. The implications of these studies for the everyday process of education are that imagery-ability can be measured from tests involving manipulation of objects in space, that the acquisition of new concepts can be facilitated by providing direct experience prior to the provision of a verbal label, and that students with low imagery-abilities are severly handicapped when they are forced to employ imaginal rather than verbal strategies. (JY)