This research proposed a new model of representational change in writing. In this<br> model, two processes — the construction phase and the expression phase — are al<br> ternatively repeated. In the construction phase, a mental representation of writing<br> tasks changes from a propositional representation of sentence-by-sentence in text to a<br> representation such as a summary of text, and finally changes into an abstract repre-<br>sentation reflecting deeper understanding. The expression phase is the reverse of the<br> construction phase; representation changes from abstract to propositional. Addition-<br>ally, this research assumed that the expression phase consisted of an automatic process<br> and a controlled process. The automatic process involves writing the main message,<br>and the controlled process involves writing another sentence that adds information to<br> the previously written sentence or gives concrete examples. After two experiments were<br> conducted to confirm the hypothesis, the results revealed that a portion of the main<br> written message was not related to the amount of resources necessary for the function-<br>ing of the control system; moreover, the amount of resources required for the proper<br> functioning of the control system facilitated a portion of the added sentences. These<br> two results are significant in proposing a new model and understanding the writing<br> process, and show that the mental process of writing includes an automatic process<br> and a controlled process.