<![CDATA[Critical thinking is a central learning outcome in geography because students are expected to interpret socio-spatial problems, evaluate evidence, and formulate reasoned solutions to contemporary population issues. However, geography instruction in many secondary classrooms remains dominated by teacher explanation and limited student inquiry, which may restrict students’ opportunities to practise higher-order thinking. This study examined the effect of the Group Investigation (GI) cooperative learning model on students’ critical thinking in the topic of population dynamics at MA Al-Khoiriyah, Bojonegoro, Indonesia. A quasi-experimental posttest-only control-group design was implemented in two Grade XI social-science classes. The experimental class learned through GI activities involving topic selection, investigation planning, field-based data collection, group analysis, presentation, and evaluation, whereas the control class received conventional instruction. Students’ critical thinking was assessed using essay tasks aligned with indicators of problem formulation, argumentation, inference, evaluation, and decision making. Data were analysed using descriptive statistics, normality and homogeneity tests, and an independent-samples t-test. The results showed that the GI class achieved a higher mean score (82.93) than the conventional class (77.93). The proportion of students in the very good category was also higher in the GI class (31%) than in the control class (13%). The independent-samples t-test indicated a statistically significant difference between groups (p = 0.007), while the assumption tests supported normality and homogeneity. These findings suggest that GI can provide a productive inquiry-oriented structure for strengthening critical thinking in geography learning.]]>
