The spinal cord conducts information from the body to the brain and impulses from the brain to the organs and muscles of the body. The spinal cord is organized into tracts each of which carries a specific type of information such as pain, temperature, touch and joint position.
I would like to talk about the tract called the posterior column which carries information about joint position. You often do not think about your joint position until it becomes uncomfortable such as when your legs have been crossed too long or your arm gets twisted behind your back. This type of information conveyed from the body to the brain and under our usual level of attention is "subconscious." This sense of where your body is in the world is called proprioception. For the most part this goes unnoticed unless you have to squeeze through a tight spot.
The lesson I think we need to learn from body position is that the position of your body projects a certain attitude. You may not even be aware of it while others who see your body position can often tell if you are angry, defiant, withdrawn, sad or happy.
I'm sure you have heard, "It's not what you said but how you said it." It is often not even how you said it, but how you stood as you said it. The way you stood or your posture is the body image you project to others.
The very interesting thing is that you can change your attitude by changing your posture. Stand up tall and feel confident. Smile and feel better. Slump your shoulders and hold your head down and feel withdrawn. Frown and feel sad. If you want to change the image you project to others you can do it by changing your posture. Change your posture and your attitude will follow. You can control your body image.