Sitting up straight isn’t about the shoulders.I was a slouchy kid (I’m now a slouchy grownup). All my life people would tell me to puff out my chest and push back my shoulders. But sitting up straight never made sense to me. Humans are animals. We’ve evolved to sit the way we do. Why would some animals evolve to sit wrong and need constant reminders to hold their muscles in uncomfortable positions? Are humans really supposed to sit up straight? And if so, how do they get their bodies to do so naturally?