Many studies have advocated the importance of teaching critical thinking (CT) skills, and have also provided some suggestions for its effective pedagogy. However, there is a dearth of research examining the efficacy of such instruction. This quantitative(quasi-experimental) and qualitative study aimed to investigate the impact of explicit instruction of critical thinking (CT) on university students’ critical thinking skills measured through the Watson-Glaser Critical Thinking Appraisal (WGCTA) used as both pre- and post-test. The participants comprised four groups of 15-16 students each. The groups received different CT treatments: Critical Linguistics (CL) and Critical Discourse Analysis (CDA) (group 1), 11 Questions (group 2), CL and CDA followed by Peer Evaluation (group 3), and a control group (group 4) that only read about CT without practicing it. After receiving instruction on CT, the three treatment groups (1-3) critically analyzed 33 texts over 11 sessions. The results of the study indicated that Group 3 (CT & CDA followed by PE) had the highest improvement in their WGCTA scores from pre-to post-test, followed by Groups 2 and 1, while the control group showed no significant gain. The findings imply that reflecting critically on language learning materials can reveal hidden cultural and ideological elements within the texts. This can significantly enhance learners' advanced thinking skills, as well as support them in resisting cultural imperialism.
