If discovered in a lab, at least we would have confirmation of the phenomenon. Researchers want to test a hypothesis. A model may argue that X should occur, so we set up the conditions in the lab to see if it does. In groups, dissonance theory's prediction that extracting costs from group members during an initiation should increase their liking for a group can be tested in the lab. Researchers want to disect an otherwise complex process.
Studies dissect the process.
Researchers want to see if a phonomenon will still occur even when they alter the setting drastically. Mook's example is the Milgram experiment.