How do psychologists define “habit”?

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.

Defining features:

1. Habit responses are activated by recurring context cues
2. 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:

1. Speed and efficiency — system 1 is fast
2. Limited thought — system 1 doesn’t need you
3. Rigidity — system 1 likes the way it already does things
4. Integration of sequences of responses that can be executed as a unit