Annie – I really believe the answer to your question is you have to be trained to look regal. – Very tight and stiff stays will help, but will not replace training or even constant nagging from a governess. All upper class European families thought they were born to rule, and a major part was looking both superior and different. Middle class families copied the upper class, so the concept trickled down the social classes.
Today we value the ideas of free expression for us and our children. Until the 1920s it was the opposite – you had to conform to accepted ideas. Here are some examples
Girls and boys were expected to always sit and stand straight. If they didn’t they were punished. If you used normal 19c school punishments today you would be in prison for cruelty/sadism etc! So, children were motivated to adopt the correct but artificial postures.
Girls, in the 19cent wore stays from very early, even babies had stay bands. Ive seen a museum example of 1880s stays for an 8 yr old. Not wasp waisted, but long with a rigid busk and a high back – no stooping in that.
As the example from C Vanderbilt tells us, rods up the back, backboards etc were used to teach upright deportment. If you cannot bend at the waist or bend your shoulders forward to stop trying and remain rigidly upright. If they weakened the muscles I don’t know how you would manage when the thing was removed (apart from a sigh of relief!)
There’s another thread Court Gowns/Dress about wedding dresses in 1913. If you look she has her arm nearly straight but her elbow is way back. Try this yourself, it is not easy, you have to pull your shoulders back. I think this would have been natural for her, she was brought up to it.
Marie in Paris