Many essayists on writing believe that a student's level of cognitive development determines the organization of thought expressed by the student's writing and that an individual cannot use language at a level that goes beyond his or her stage of cognitive development. Without the maturation of formal operational structures, students cannot easily take a view contrary to their own positions (decentering), so that unless writing activities relate to the students' own perceptions of the world, assignments will be misdirected. Activities that encourage students to make inferences also require the full development of formal-operational structures. Only at this level can a student make a real synthesis--recognizing that an opposing position has genuine validities that can provide multiple perspectives on an issue. An exercise used at Memphis State University (Tennessee) helps students synthesize. Two fund-raising letters are examined in which the intended audiences are analyzed, the logical and persuasive fallacies are explored, and the rhetorical strategies employed by the writers are determined. Students then write an essay on one of the letters in which they assume the role of the recipient, describing that recipient's possible reaction to the letter, and comparing that response to the response the letter's author intended to elicit in the target audience. Such assignments help encourage students to perform successfully at the developmental level they have reached, as does teaching writing with the workshop method and with the "one-on-one" method of peer and professional conferences. (Notes and references are included.) (NKA)