Negotiating Talents of a Two Year Old

So Lana has understood "If..Then.." type stuff for a while. She usually only gets dessert at dinner if she eats enough - preferably of everything - but we've also sometimes given it to her if she tries something new. Somehow the other night, she convinced us if she would eat some of her chicken with her potatoes (from chicken and biscuits dinner last week), she could have a cookie. Well, that must mean if she ate two pieces of chicken, she got two cookies. At least, that's what she told us. We had to give it to her if only because it was too funny and completely logical.