This present study aimed to investigate students’ critical thinking in the debate practiced by undergraduate students. Critical thinking here has four levels: lower, higher, complex, and metacognitive levels. This study focused on the representation of critical thinking in each debate. It elaborated the reasons why students’ critical thinking belongs to those level. Furthermore, it gave insights on how students’ critical thinking level determined their winning in the debate.
A case study was employed to conduct this research. 19 third semester undergraduate students and their lecturer participated in this present study. The data of this study were the students’ performances, video transcript, and interview transcripts. There are 9 video transcripts and 3 interview transcripts analyzed. Three debate performances representing the students’ critical thinking representation and students’ critical thinking level. Their lecturer was interviewed to give more detailed data. Then, the data were analyzed using interactive model which has four steps: data collection, data condensation, data display, and drawing conclusion.
The results show that students with high critical thinking level could bring more convincing arguments than the students with a low critical thinking level. It proves that the higher level of critical thinking in the debate, the higher score, and the better performance will be. Accordingly, the students apply critical thinking to interact and persuade both the audiences and the adjudicator. Moreover, the students faced both cultural and non-cultural challenges in applying their critical thinking. This study implies that the explicit teaching of critical thinking is necessary to undergraduate students. Thus, the lecturer needs to make clearer speaking instructions to avoid misunderstanding.

Keywords: English debate, Critical thinking, Argumentation, Speaking ability