The 9 experiments reported indicate that adjectival modification of nouns at list presentation disrupts item recall (N) and clustering (RR) in free recall when the arrangement of modifiers is inappropriate for the nouns and when each modifier is specific to 1 noun of a list, under a number of experimental conditions. Modification conditions vary in the effects they have, and the effects vary with certain instructional conditions. Modification effects are found when the retention test is 1 of recognition and persist when the modifier occurs before and after the noun. Block presentation did not overcome the effects of modification on RR and N, and when Ss were forced to match list length at recall, Ss did not add correct responses or relevant intrusions as often with modified as they did with unmodified nouns. In addition to list length, the factors responsible for the differences between modified and unmodified nouns seem to be disruption of the category membership of the nouns or of their intracategory interitem associations. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.