This study replicates VanPatten and Cadierno (1993) in an attempt to determine whether or not explicit information given to learners receiving processing instruction is responsible for the beneficial effects of instruction. Fifty-nine subjects were divided into three groups: (1) one receiving processing instruction in object pronouns and word order in Spanish as in VanPatten and Cadierno (1993), (2) another receiving explanation only with no activities or practice, (3) and another receiving only the structured input activities with no explanation. A pretest/post-test assessment was used involving two tests, an interpretation test and a sentence-level production test. Results showed that the beneficial effects of instruction were due to the structured input activities and not to the explicit information (explanation) provided to learners.