The study showed a striking correlation between personality and posture. Ninety-six percent of the subjects who had ideal posture and eighty-three percent of the subjects who had kyphosis-lordosis posture were extraverts. The introverts, on the other hand, were far more likely to have flat back or sway-back posture.
The results of the study alone are noteworthy, but understanding the reason why extraverts and introverts tend to stand differently is fascinating: It goes back to our ancient physical responses to positive and negative stress. When we feel confident, our action response kicks in, prompting us to stand up straight and arch our back, preparing for action. Extraverts tend to feel and act confidently, and repeated activation of the action response can lead extraverts to stand in this posture all the time.
In contrast, when we feel timid, fearful or don't want to be the center of attention, our withdrawal response is triggered. The withdrawal response causes us to contract our abdominal muscles as if to curl up into the fetal position so we feel protected. When we contract our abdominal muscles, we tuck our pelvis under and the natural arch in our lower back is flattened, resulting in the flat back or sway-back postures common among introverts.
So, how do you determine what kind of posture you favor and what can you do to improve it?