Nope, that's not what I'm looking for either. So, it might be easier to explain if I relate it to focus group type studies. Let's say you were asked to be in a focus group about Domino's pizza (yes, I drew inspiration from those really lame commercials).
If you were asked questions about Domino's pizza, you might be motivated to respond in a way that would agree with what you believed the researchers were attempting to determine (let's say the researchers were trying to find a link between consuming pizza and increased health). You might say, knowing the goal of the study, that you feel healthier after you eat a pizza, even though you really don't.
I'm pretty sure there is a word to describe such bias. Just can't think of it. Not a random ? either, I need it to finish up my own research project :/