An examination of student papers from three universities on the same tasks revealed that expository writing tasks were less demanding cognitively than argumentative writing tasks and that argumentative writing tasks were less demanding than speculative tasks. Another finding was that when students were able to translate a generalized task into personally meaningful problems, they used more sophisticated strategies. These findings suggest that writing tasks should be designed sequentially to stimulate students to operate on cognitive levels that challenge their thinking and engage their interest so that they will be motivated to draw upon the resources they possess. Summary writing offers such potential. Students can be shown that summaries have "cognitive levels" that can be related to the use of reading materials as sources for developing their ideas. Summaries at the restatement level, which draw on the text's actual language, are analogous to the use of direct quotations in their writing. Summaries at the descriptive level, which follow sequentially the text's main arguments, are related to the use of paraphrase in their writing. And summary writing at the analytic level, which requires students to take arguments apart to see how they are constructed, prepares them to view the reading texts critically and to use them as take-off points in exploring their own thinking. (HOD)