Studies of the length-difficulty relation in serial memorization

The relation between the amount of free study time needed to prepare for a perfect serial recitation and the number of words in the list was determined for individual subjects when intralist segmentation was systematically varied by the experimenter and when it was left entirely up to the learner. It was found that list organization, regardless of source, failed to affect difficulty. The length-difficulty relation for a given kind of material is therefore a single, nondecomposable function whose shape is determined solely by the number of items in the list and not at all by how those items are segmented. What the learner gains by subdividing a list into groups is precisely what he loses by having to cope with the groups.