The cue-routine-reward framework
The classic behavior change model is based on the cue-routine-reward framework. This works by the simple principle that a trigger makes you act (cue), with a consistent behavior (routine), possibly resulting in a positive event (reward). For example, you may feel sleepy in the morning. This is the cue, which triggers the drinking coffee routine, possibly resulting in being more alert, increased concentration, and increased dopamine levels. Overall, you might feel good, as a reward. This, in turn, strengthens the association between cue and routine, so it's more likely that tomorrow morning you will also have coffee.
For the routine, conscious thought is not required. If you are a coffee lover, you will most likely not think whether to drink a cup or not, you just drink it. The cue-routine-reward framework is so strong that sometimes it can go against your conscious decisions. This is what people usually call an addiction.
The most direct way is using a highly...