Understanding Sensor Notifications on Mobile Devices

Abstract

Mobile devices, such as smartphones and tablets, use notifications to inform their users of events. Some security- and privacy-related events are time-sensitive: the user must be notified immediately. In this paper, we perform a user study with 40 participants to understand the properties of such time-sensitive notifications. We specifically focus on sensor notifications that notify the users when one of the sensitive sensors, such as camera, microphone, or location is being accessed. We show that none of the notification channels available on mobile devices, i.e., LED, vibration, sound, and display, can grab the user's attention in more than 24% of the time. Among them, vibration achieves the best success rates on average. Moreover, our results show that less intrusive channels, e.g., display, can achieve significantly better results if the device's physical context, i.e., ambient light intensity, is considered. Based on our findings, we suggest that display notification is the best option for camera while different vibration patterns are best options for microphone and location sensor.