Tactual shape perception in relation to the understanding of geometrical concepts by blind students

Abstract

Tactual shape perception is a synthesis of many parameters which lead blind students to make sense of external stimuli. It is vital to investigate this field of perception because it reveals many differences between passive and active touch. The van Hiele model provides a tool for investigating and classifying students' thinking in geometry. In a study of 19 blind and visually impaired students in a special school in Greece, we sought to understand their own way of approaching, developing and understanding concepts of shape. The findings support on one hand the appropriateness of the van Hiele theory and on the other the complexity of tactual shape perception and its uniqueness with respect to every student's thinking. Teachers and specialists can enrich their understanding and be more effective when teaching geometrical concepts that require taking into account variables such as: touch, movement, posture, type of shape, language, prior knowledge and the conditions of the task.