Description

Muller Layer Illusions Apparatus PSAW To determine the extent of space error, movement error and error in perception of length of a line. The instrument consists of a stand with a wooden block. The wooden block on the front has a thick straight line with a fixed arrow and two movable arrow pointer of the same lenght. The arrows are made in such a way that they act as open ended or closed embedded arrows. On the rear side of the block a wooden scale is imbedded. a certain lenght of the line is fixed between two closed arrows and the subject is asked to adjust the lenght of the line equal to the fixed line with the help of pointer. The error in perception is measured with the help of scale at the rear.