Just as the fencer reflex (ATNR) splits the body down the middle, hindering left-right coordination, this cat-sit reflex (STNR) splits the body across the middle, hindering top-bottom communication. As long as the STNR remains imperfectly integrated, a human being cannot attain fully upright posture -- because the reflex dictates that when the upper body is extended, the hips and knees want to flex.