The effect of stimulus exposure in semantic verification task within the framework of two levels of complexity of experimental context was examined in nine experiments. The complexity of experimental context was defined in terms of number of constitutive elements of a statement (subject, predicate and copula) which vary in the course of an experiment. Four experiments with different exposure duration have been performed within the framework of minimal complexity (where only one element of statement varies), while five experiments with different exposure duration have been conducted within the framework of medium complexity (where two elements of statement vary). Systematic manipulation of the two variables (i.e. complexity and exposure duration) provides variation of processing load in verification process, thus influencing the efficiency of working memory during the verification task. The obtained results indicate that the cognitive load variation (defined in terms of variation of exposure duration) affects processing of subject-predicate congruency, which is an obligatory step in statement verification. The shorter the exposure duration, the bigger the difference in processing latencies between “congruent” and “incongruent” statements. The effects are more pronounced for statements presented in the framework of medium complexity. Also, the reduction of exposure duration affects the error rate as well as processing of statement’s quality (i.e. affirmative vs. negative form of a statement).