This...

5 minutes ago, I asked the little girls who would like to go jump in the bounce house. N (5) and K (2.75) yelled ME and went running downstairs.

T (17.5 months) pointed to herself, and yelled "this" and ran downstairs to join her sisters.

Edited: I just love it when little ones say, "Me" or show that they understand they are distinct. This is the concept of self. This article discusses self-concept and assessing it.

T has said, "Me" before when echoing her sisters... Yesterday she said, "This." I thought it was really cute. I wonder if self-concept develops differently in first-born children versus not first-born. When we get into self-concept development in my class, I will do a scan of the literature and see what research (if any) has been done.