Covert conditioning is an interesting variant of operant conditioning where, instead of using an external stimulus to modify someone's behaviors, you just have them imagine themselves doing things and then receiving rewards or punishments. For instance, an alcoholic could imagine drinking alcohol and then immediately feeling nauseated. Or a student could imagine deciding to do his homework and then suddenly winning a million dollars.

Unfortunately, I'm not sure whether covert conditioning works. The linked Wikipedia article doesn't really give much evidence. If covert conditioning works, it seems like it could be very useful, especially in situations where ordinary reinforcement techniques are hard to use. For instance, one could easily reinforce sociability, which is hard to reinforce through ordinary methods because you don't want to look weird in public. Or one could train oneself to avoid unhealthy food by imagining that it makes one nauseated, precluding the need for actual emetics.

(Not going anywhere in particular with this, just curious what people's thoughts are.)