Conducted 4 experiments with college students (N = 83) in which stimuli selected from a set of nonsense patterns similar to alphanumeric characters were degraded by reproducing each basic drawing through more and more layers of superimposed transparent plastic to secure various levels of objective clarity. A stimulus was temporally repeated to Ss 6 times in the same location. Identifiability and rated clarity of stimuli increased with increasing objective clarity and/or stimulus duration, even in the absence of prior knowledge about the stimulus set. However, with increasing repetitions, identifiability increased while rated clarity did not. It is concluded that, since there was no concomitant improvement in perceptual clarity as stimulus identification improved across repetitions, the former could not be the cause of the improvement in the latter. (PsycINFO Database Record (c) 2006 APA, all rights reserved)