The rhetorical functions of syntactically complex sentences in social science research article introductions

There have been increasing calls for research attention to the linguistic realizations of rhetorical functions in academic writing. Research in this area has so far focused primarily on lexical and phraseological features. While numerous studies have investigated the relationship of syntactic complexity to language proficiency, development, and writing quality, research examining the rhetorical functions of complex syntactic structures is scant. This study analyzes the rhetorical functions of syntactically complex sentences in the Corpus of Social Science Research Article Introductions, which contains the introduction sections of 600 published research articles in six social science disciplines. All samples were annotated for rhetorical moves and steps using an adapted version of Swales' (2004) revised Create a Research Space model, and all sentences were assessed for syntactic complexity using multiple measures of global complexity, finite subordination, clausal elaboration, and phrasal complexity. Results revealed significant variation in syntactic complexity among sentences realizing different rhetorical functions and expert writers' employment of complex structures to realize different rhetorical goals. The implications of our findings for academic writing research, pedagogy and assessment are discussed.