Despite the existing extensive research on stance markers such as hedges, boosters, and self-mention in academic writing, few studies, however, examined the co-occurrence of these stance markers to help authors project their identities in writing. In this study, we examine how self-mention with boosters and hedges are used by writers of different groups to manifest authorial presence and what functions they realize in research writing. Two self-compiled corpora were constructed to compare the discursive practice between Chinese PhD students and journal article writers from four disciplines in hard applied and hard pure science. In general, student writers use fewer self-mention with boosters but more self-mention with hedges than expert writers. An examination of the rhetorical functions of these devices shows that both expert and student writers employ most self-mention with boosters for presenting research findings, but students are more inclined to invest self-mention with boosters than expert writers when describing research procedures or elaborating arguments. Meanwhile, self-mention with hedges are mostly used for elaborating arguments, but compared with expert writers, students seem to overly obscure their presence in this function.
