“…This "hierarchical" type of structure has been advocated for use in classroom instruction by educational psychologists in order to make material more comprehensible (Briggs, 1968;Gagne, 1970;Gagne & Brown, 1961;Gagne & Rohwer, 1969). Several researchers have shown the effectiveness of such a method in controlled situations (Eustace, 1969;Lee, 1968) and have shown that the more complex the task is, the smaller and simpler the component steps should be (Naylor & Briggs, 1963). As a result of and in addition to making instructional material more comprehensible, this kind of "hierarchical" segmentation tends to make it more memorable.…”