LocknType - Lockout Task Intervention for Discouraging Smartphone App Use.

Instant access and gratification make it difficult for us to self-limit the use of smartphone apps. We hypothesize that a slight increase in the interaction cost of accessing an app could successfully discourage app use. We propose a proactive intervention that requests users to perform a simple lockout task (e.g., typing a fixed length number) whenever a target app is launched. We investigate how a lockout task with varying workloads (i.e., pause only without number input, 10-digit input, and 30-digit input) influence a user's decision making, by a 3-week, in-situ experiment with 40 participants. Our findings show that even the pause-only task that requires a user to press a button to proceed discouraged an average of 13.1% of app use, and the 30-digit-input task discouraged 47.5%. We derived determinants of app use and non-use decision making for a given lockout task. We further provide implications for persuasive technology design for discouraging undesired behaviors.