PERSONAL SPACE PERCEPTION IN HUMANS / 体力科学

ABSTRACT

To examine personal space perception, a method of identifying joint position was determined by having the subject equally bisect the joint angle, by producing a minimum increment in change of position and by selecting a threshold for two-point discrimination using the metacarpophalangeal joint of digits 2-5.<BR>Eight healthy adults (6 males and 2 females) were used as subjects. The subjects' eyes were covered at all times to prevent any visual feedback.<BR>Each metacarpophalangeal joint of digits 2-5 was extended, flexed and pointed to the bisection position in 6 sec (about 2 sec in each position) . The difference in the bisection position selected using the index finger with the shoulder, elbow and hand in variety of positions was determined. The deviation from the mid-bisection point and the standard deviation were less when the hand was positioned most comfortably and near the face (“natural and near”) than when the hand was positioned in the more uncomfortable position and further from the face (“unnatural and further”) .<BR>In a second test, the index finger was moved from full extension to the full flexion in increments as small as possible at a rate of one change in position per second. Again, the effect of arm position was determined.<BR>In case of“the natural and near”position, each increment in joint position was smaller than in“the unnatural and further”position.<BR>In“the natural and near”position, the two point threshold was smallest of all. It was measured at the thumb side of right palm in the proximo-distal direction.<BR>These results suggest that personal space perception of metacarpophalangeal joint is affected by the position of adjoining limb segments.