Time for me to demonstrate why they call it a degree in the PHilosophy of economics. In part, this is an esoteric problem that very few people should care about. In part, it's fundamental to what we as economists can say about the world based on the data we have available. Last week I learned that the relationship between what I buy at the store, what I would say on a survey are my food preferences, what I would tell a bunch of Econ101 students about my food demand, and what shows up in experimental data as my food preferences all give very different answers to my food preferences. Even if we are careful about definitions, it's a terrible mess.
... Edit Update: I spoke to the experimenters and decided that I couldn't describe the economic lessons I wanted to without potentially compromising their future runs if a future test subject read my post. I will re-post it when the sessions have ended, which should be before the summer.