Such a contrast at times between the children. Some are have smiles as wide as can be, giggling and happy, and others are quite reserved and quiet. It doesn't mean they're any less happy, but just, seems they learn to behave differently for photos. I'm not quite sure what it is that seems to cause this in Mali.
Nowadays, in the West, it would seem quite odd to go somewhere and see young children spending their day mostly working, but when you're in Mali and other extremely poor countries, it's the norm. It doesn't make it any easier to see how difficult the lives are of these children, but you can always see where the child comes out to play even when working. After all, they're children!