How do people adhere to goals when willpower is low? The profits (and pitfalls) of strong habits.

Across 5 studies, we tested whether habits can improve (as well as derail) goal pursuit when people have limited willpower. Habits are repeated responses automatically triggered by cues in the performance context. Because the impetus for responding is outsourced to contextual cues, habit performance does not depend on the finite self-control resources required for more deliberative actions. When these resources are limited, people are unable to deliberatively choose or inhibit responses, and they become locked into repeating their habits. Thus, depletion increases habit performance. Furthermore, because the habit-cuing mechanism is blind to people's current goals, depletion should boost the performance of both desirable and undesirable habits. This habit boost effect emerged consistently across experiments in the field (Studies 1-2) and in the laboratory (Studies 3-4), as well as in a correlational study using a trait measure of self-control (Study 5). Given that many of people's habits in daily life are congruent with their goals, habit processes can improve goal adherence when self-control is low.