There’s a certain point, I think, when an older sister becomes a big sister. It might be soon after the birth of little brother; it might take a few years. Really, it all depends on the age of the sister, I think.

But at some point, sooner or later, older sisters begin taking on themselves some of the responsibilities of looking after little brother. It might begin with playtime: “L, keep E in your room for a while as I start getting dinner ready” might be a first step.

That’s a relatively easy step. Big sister can half do her own thing, half entertain the Boy. The fact that they’re in her room adds a degree of security: she certainly won’t let E get into all that much because he has a tendency to mess things up.

The real transition comes when big sister begins fulfilling some of the lower needs on Maslow’s hierarchy.

These are the responsibilities that aren’t just fun. They’re not low-engagement responsibilities.

And when the older sister begins taking on those kinds of little jobs, we say, “Welcome, Big Sister! We’ve been waiting for you!”