Through my experiences in education, I've generally observed that students appear to have a relatively superficial understanding of what plagiarism is and why it's wrong. Because of the general lack of deep understanding of the issue, along with its potential repercussions, I feel that learning about plagiarism is critical to student growth and development. Traditional approaches to plagiarism education tend to be based on the misconceptions model for learning. Perhaps a better approach to promoting student learning about the issues surrounding plagiarism could be based on a cognitive resources conceptual model involving students' personal epistemological resources.
It is my experience that students reach relatively fast and easy agreement that wholesale "copy and paste" without citation is plagiarism and is wrong. Students can see that such actions deny credit to others who have put forth significant effort, and that this type of plagiarism clearly inhibit the teacher's ability to assess their personal understanding of the knowledge or skill at hand. Students do admit that it happens, but tend to blame the behavior on laziness and/or procrastination. However, in situations in which they submit work in a good-faith attempts to complete assignments according to teacher instructions, students are in much greater disagreement with regard to the more abstract forms of plagiarism that involve using ideas and/or structures of ideas without citation. For example, students are often challenged to do research for assignments, and are instructed to express "in their own words" the information they find. Many students feel that an idea that has been re-worded is sufficiently different enough from the original that citation is not required, while others feel that ideas taken from others must be cited even if expressed in alternate wording. Some students can see extensions of the issue of citation, and question whether the teacher should be cited for ideas transmitted orally in class or otherwise.
Students can become frustrated when confronted with rigorous interpretations of plagiarism that require comprehensive citation. The position of such students tends to be, in essence, that ideas are so fundamentally dependent on other non-original knowledge that they can't be copied (ie: only the expression of ideas can be copied). In other words, student frustrations about citation rules seem to be influenced by their understanding of the complexity of the "heredity" of ideas. Simply put, these students feel that ideas are either observations available to anyone or are already so dependent on other foundational concepts that they don't deserve qualification as original; in neither case is citation viewed as necessary. I think it's important to acknowledge that there is significant understanding about the origin and nature of ideas underlying the position that new ideas are based on pre-existing ideas. Perhaps the frustration these students experience has to do with uncertainty on how far back citation has to go in order to avoid plagiarism. These are pretty insightful thoughts and completely valid concerns, given that plagiarism and its significant consequences are presented in a very black & white, right & wrong dichotomy. I think these students are putting forth the effort to promote their own learning and to follow their teachers' guidelines and want a clear set of rules on how to avoid crossing the line and committing plagiarism.
As I've been thinking about student understanding of plagiarism and its fundamental relationship with concepts on the origin and nature of ideas, I've remembered some reading I did in grad school on personal epistemology (Hofer, 2001) and on using epistemological resources in physics education (Hammer & Elby, 2003). At this stage my thoughts are still in a very formative stage with regard to using epistemological resources in plagiarism education. However, it seems to me very clear that the students I've encountered do have concepts of knowledge and knowing that are activated when they discuss plagiarism. Furthermore, it also seems clear to me that students could benefit from improvements to plagiarism education that would move it beyond the misconceptions approach and into a cognitive resources approach. Efforts in this direction include the book "Originality, Imitation, and Plagiarism" edited by Eisner and Vicinus highlighted by Inside Higher Education, which also highlighted specific plagiarism education methods presented by Hagopian and others at a recent conference on college writing. My hope is that further development of a conceptual model for student thinking on plagiarism, based on epistemological cognitive resources, will advance student and teacher understanding of a topic that is clearly more complex than a misconception of academic integrity.
EDIT: After posting this I decided to do a Google search on "plagiarism and epistemology", wondering if anyone else was thinking on the same track. Although it seems we've come to it from somewhat different paths, Rebecca Moore Howard has much more extensive and refined work on the epistemology of plagiarism, the afore-linked presented at a conference (called "Originality, Imitation, and Plagiarism") at the University of Michigan in 2005. As is clear from her publications list, I've got lots of reading to do - and I'm sure I'll find even more. It's going to be interesting to explore applying these ideas with secondary-level students ... perhaps I'll even find others in secondary-ed who are already on this track, too. I'll keep posting on this, but wanted to edit this post to include this disclaimer to avoid any potential appearance plagiarism on my own part!
Hammer, D. and Elby, A. (2003). Tapping Epistemological Resources for Learning Physics. Journal of the Learning Sciences, 12, 53-90.
Hofer, B. (2001). Personal epistemology research: Implications for learning and
instruction. Educational Psychology Review, 13(4), 353-382.