#giving

At what age do children understand charity work?

The school is promoting a solidarity campaign in which we are supposed to deliver boxes to needy families with some basic goods. Each member of the family should make an outline of their hand as a symbolic gesture of "giving someone a hand", but my 8yo daughter refuses to do it. She also complained that we never buy her the kinds of biscuits that are in the box. She of course is too young to understand the importance of this, but I got pretty disappointed because I was expecting her to engage. What should I expect at this age?