<![CDATA[Students often struggle to transform concrete representations into formal mathematical representations in geometry because they differ in how they receive, process, and understand information. Abstraction theory provides a useful framework for understanding how students develop geometric concepts. This qualitative study explored students' processes of mathematical abstraction in understanding the concept of triangles, based on Field-Dependent (FD) and Field-Independent (FI) cognitive styles. The analysis was guided by eight aspects of mathematical abstraction, integrating empirical and theoretical abstraction with the processes of generalization and representation. Two seventh-grade students from a junior high school in Palu, Indonesia, were purposively selected through the Group Embedded Figures Test (GEFT) to represent the FD and FI cognitive styles. Data were collected through triangle-related tasks and semi-structured interviews. The findings revealed that FD students focused on observable visual features and generalized concepts based on shape similarities, resulting in simple representations that relied primarily on pictorial forms. In contrast, FI students identified relationships among geometric elements, generalized concepts based on structural properties, and represented concepts in a more formal and idealized manner. These findings suggest that cognitive style influences students' mathematical abstraction processes and highlight the importance of geometry instruction that accommodates students' cognitive characteristics to support effective concept formation.]]>
