Results of 2 experiments with undergraduates (N = 41) reveal that words masked by upright random letters in a wordlike array or by unrelated words were more difficult to read than words masked by other patterns, including strings of complete letters in random orientation. This difference was not observed when targets were figures to be identified. This result suggests that a wordlike mask made of letters set up a reading response that interferes with the processing of a target when the target requires reading. (PsycINFO Database Record (c) 2006 APA, all rights reserved)