This paper revisits Swain’s Pushed Output Hypothesis to set a basis for explaining the merits of reading for writing in L2 instruction. Writing assignments are a type of pushed output that help students understand the gap between what they would like to communicate and what they are able to communicate. Although the gap results from lack of linguistic ability in syntax as well as lexis, this paper will focus on how reciprocal reinforcement in reading and writing creates a greater depth of semantic processing that aids in greater retention of newly acquired vocabulary words. Reciprocal reinforcement of vocabulary in reading-for-writing lessons can aid in raising students awareness of their gaps between understanding new vocabulary and being able use those words to create meaningful messages. This conscious-raising function of reciprocal reinforcement triggers cognitive processes such as language learners testing their individual hypotheses of how the target language works.