Studies of the length-difficulty relation in serial memorization

The category size effect in serial memorization.

“…Because Wickelgren's (1967) data show the largest effects under ordered recall scoring, the present paper will focus on serial, or ordered, recall. It is also with such a constraint that Martin et al (1977) report no differences, and so it is there that the discrepancy is the clearest. The use of a free study time procedure has perhaps spawned some new interest in the classic lengthdifficulty relationship in serial learning.…”

“…The use of a free study time procedure has perhaps spawned some new interest in the classic lengthdifficulty relationship in serial learning. Recently explored by Derks (1974) and extended by Martin et al (1977), the technique, wherein learners are allowed to study a complete sequence until they feel capable of ordered recall, has generated promising data. It is from just such a set of data that Martin et al (1977, Experiment 3) have argued for the sole importance of list length as a determiner of difficulty.…”

The length-difficulty relation in serial memorization of words, pictures, and snowflakes

“…In other words, over the range tested, a doubling in list length resulted in approximately a sixfold increase in study time. Although changes in subjective organization that correspond to list length changes might have accounted for this ratio relationship, Martin et al (1977) manipulated subjective organization and found that the power function, or something very much like it, continued to appear. They concluded that "the length-difficulty relation is not decomposable" and, on the basis of some of the same data, that this function "has no universal shape."…”