I seem to recall, when reading the literature on this subject, that the sticky variable is going to be "sufficient motivation." What motivated him today may not be what motivates him tomorrow, and what motivates Jedi may or may not be what motivates Jezibel. I am looking at my parents feline subject, and she appears to have no motivation to do anything at all whatsoever right now.

However, if you can design an experiment that attempts to measure the sufficient motivation variable, I bet you can get funding.