In order to examine the personal space perception, measurements were conducted on both elbows in 14 men and 46 women. Each subject, with his (or her) eyes closed and with his upper arm fixed horizontally, was instructed to stop the vertical and horizontal swing motion of his lower arm at the point he considered to be the middle of the range of possible motion on the front and side of plane at his shoulder, and this was repeated ten times. In various conditions, similar measurements were also done to study factors affecting the personal space perception in 14 men.
Mean values of bisected angles in percentage against range of motion were deviated from the middle points in the direction of the elbow extension, although there were large differences between the individuals. The deviation was smallest in the vertical. side of plane, and was larger in the horizontal plane than that in the vertical plane. The deviation was not so much affected by the various conditions.
It was suggested that the gain of the personal space perception is higher in the elbow extension than in the elbow flexion and its difference is larger in the horizontal plane than in vertical plane of the human elbow joint.