People who are going to talk, are going to talk, people who aren't going to talk, aren't going to talk. If you offer someone who isn't going to talk a cookie for talking, they'll make a very, very vain attempt to say whatever meets the lowest possible requirement to get that cookie, and nothing more. The person who already talks will get that same cookie, but they'll be no more or less productive in conversation than before. This objective does nothing but make Unity and it's chat feature a clusterfuck of people who don't want to talk, but talk anyways to get their 500 XP/100 Accolades, aka, their cookie.