Susceptibility to the Muller-Lyer illusion

The problem to be examined in this study was whether or not there is a significant relationship between norma1 and retarded children in the haptic perception of the Muller-Lyer illusion. In a study of this nature, it is essential to control variables among the subjects in order to determine the actual causes of any differences between the normal and the retarded children. Because of this, four questions were raised. 1. Do differences exist in haptic perception between normal children and retarded children with similar chronological ages? 2. Do differences exist in the tactual perception between boys and girls? 3. Do differences exist in the intratrial results between the normal and retarded children? 4. Do differences exist in the intratrial results between boys and girls?