Abstract
Environmental Geography in higher education faces challenges in empowering students to navigate complex ecological issues, a problem often exacerbated by traditional textbooks lacking real-world context. This hinders the development of essential critical thinking skills (CTS) and dispositions (CTD). Addressing this gap, this study developed and validated a constructivist-based textbook integrated with the project-based learning (PjBL) model. Employing an Educational Research and Development (R&D) design, the study encompassed expert validation, progressive preliminary trials, and a main operational field test involving 31 geography education students in Indonesia. Effectiveness was evaluated using a one-group pre-test-post-test design, utilizing the California Critical Thinking Disposition Inventory (CCTDI) and a rubric-based essay test. Results indicated that the textbook was highly valid across language, design, and content dimensions. Following implementation, students’ CTD significantly improved from the “fair” to “good” category (n-Gain = 0.12), and CTS advanced from the “poor” to “good” category (n-Gain = 0.37). Paired sample t-tests confirmed statistically significant enhancements for both variables (p < .001). Furthermore, student responses were overwhelmingly positive (82.19%), reflecting high pedagogical engagement. These findings demonstrate that integrating constructivist PjBL syntax into textbooks successfully bridges the gap between abstract theoretical knowledge and practical critical reasoning. This study advocates for the wider adoption of such interactive instructional materials to foster higher-order thinking in global geography curricula.
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Article Type: Research Article
EUR J SUSTAIN DEV RES, Volume 10, Issue 3, 2026, Article No: em0414
https://doi.org/10.29333/ejosdr/18933
Publication date: 07 Jul 2026
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