Used 2 modes of strengthening or priming responses in 2 experimental examinations of the effect of set on tachistoscopic thresholds. In Exp. I, results showed evidence of the influence of response availability upon thresholds, while Exp. II showed a perceptual sensitization effect. In Exp. I, 15 undergraduates named the states of the Union and then measured thresholds for the named states, the unnamed ones, and control words; both the named and unnamed states had thresholds significantly lower than control words. In Exp. II, 32 undergraduates pronounced words on 5 trials from stimulus cards showing some words, pictures, and definitions. Although the words that had been evoked from pictures and from definitions were more easily recalled than words given as responses to the printed words themselves, the latter materials were most easily recognized in the subsequent threshold measurement. Thus, there appeared to be a sensitization effect accruing from previous viewing of printed words that did not occur where verbal responses had been evoked by pictures or by definitions. (17 ref.) (PsycINFO Database Record (c) 2006 APA, all rights reserved)