Shame

Today Jillian apologized for going poop in the bath tub. She repeatedly said "sowy" and I had to tell her it was okay and give her a hug before she felt better. At this age her muscles are still weak and not fully in her control so these things happen and we don't scold her for it. That brings me to the question, why was she ashamed? Where do children pick up things like shame for having an accident at under 2 years old or thinking that going poop is bad (like one of Jillian's cousins)? Is it a matter of the child's personality, environmental factors or both? Normally I would jump straight to environmental but there is no way that could be it in our case. Jillian is not really potty training so she hasn't been taught what an accident is, we never scold her for peeing or pooping when her diaper is off as she obviously can't help it, and we are the only ones that give her a bath or have her run naked. It broke my heart seeing my baby girl apologize for something out of her control and that is completely natural.