Two USC psychologists have a nice survey paper on the psychology of habit.
How do they define “habit”?
Habits are a type of automatic response that are learned and have some specific defining features.
Automatic response — No conscious decision or executive control is required to activate the response after perception of a context cue.
Learned — Differs from an instinct or a knee-jerk reaction. Habits have to be learned through repeated pairing of context and response.
- Habit responses are activated by recurring context cues
- Habit responses are insensitive to short-term changes in goals, including changes in the value of outcomes, and changes in the response-outcome contingency
Additional features may apply:
- Speed and efficiency — system 1 is fast
- Limited thought — system 1 doesn’t need you
- Rigidity — system 1 likes the way it already does things
- Integration of sequences of responses that can be executed as a unit