Eli5: why do babies sit with perfect posture when they learn to sit, but the older you get, the worse it gets?

Question

Babies sit straight up naturally. But the rest of us have to put effort in to having good posture, why?

In: 1304

Answer 1

Because we as a species don’t emphasise the importance of posture. We emphasise chasing money, fame and sex which leads us to becoming miserable bent over hunchbacks.