Smartphone habits are stronger in spaces chosen out of habit.

Habits are a fundamental driver of human behavior. However, prior research has largely studied habits in isolation. This study investigates spatial and smartphone habits-two cornerstone habits in contemporary society-in tandem, revealing the multiplicative ways in which habitual processes can underlie human behavior. We provide evidence that smartphone habits are stronger in habitually traveled and visited spaces. We leverage a custom-designed app that logged mobility and app use while prompting map-based questionnaires of participants' trips for two weeks (N = 419 participants; n = 27,446,977 GPS and app logs; n = 7,226 trip questionnaires). Overall, app habit strength predicted higher likelihood of app use (vs. non-use) and more app use (when used) on more habitually travelled routes and in more habitually visited destinations. The interaction between spatial and smartphone habits was most consistent for objective (vs. subjective) habit indicators. Social app habits were stronger and more context-independent than non-social app habits. Altogether, our findings reveal how distinct habitual processes can combine to shape daily behavior. Further, our method illustrates the potential of linking mobile sensing and surveying to measure habits in the real world.