Well, we have dueling anecdotes, which makes it sound like it's time for a study. ;-)
(Unfortunately from what I can tell, the studies on how different kinds of motivation [intrinsic, tangible extrinsic, social, etc.] relate are all over the map, and appear to depend sensitively on the specific kind of task and setting.)
I don't think you have dueling anecdotes, just observation of the existence of red weasels and blue weasels. Until someone starts claiming that most weasels are some color, or that certain colored weasels tend to occur in certain kinds of environments, there's no need to fund extensive studies ;)
(Unfortunately from what I can tell, the studies on how different kinds of motivation [intrinsic, tangible extrinsic, social, etc.] relate are all over the map, and appear to depend sensitively on the specific kind of task and setting.)