The effect of topic familiarity on critical thinking skills of Thai secondary students at different English writing ability levels

Critical thinking is one of the 21st century skills and has become a main goal in education. It is often referred to as argumentative skills since one must also be a critical thinker in order to form a sound argument. Many research studies explored students’ critical thinking ability through their argumentative essays and found that topic familiarity plays a role in writing performance, especially at the university level. However, only few studies have explored how topic familiarity affects the argumentative skills of secondary students with different English writing ability levels in EFL context. To fill this gap, this study aims to investigate the effects of topic familiarity toward the written argumentative skill of Thai secondary students with different English writing abilities through two aspects: the quality or total scores of arguments and the complexity of argumentation. 37 Thai secondary students were categorized into low, moderate and high levels in accordance with their writing ability. They were assigned to write four argumentative essays responding to familiar and unfamiliar topics. The essays were graded in accordance with Stapleton & Wu’s Analytic Scoring Rubric (2015) before t-test was applied. The findings revealed that the total scores of the essays on the familiar topics formed by the students at all levels were not significantly higher than those on the unfamiliar topics. However, their essays on the familiar topics showed more complexity with higher argumentative elements. The findings indicated that the familiar topics encourage the application of more complex arguments but do not always contribute to higher quality of the arguments.