People act to protect privacy – after learning how often apps share personal information

During the first week of the study, app behavior data was collected for twenty-three people as they used their own Android mobile devices. In the second week, they were given access to AppOps, and in the third and final phase they received the daily privacy nudges detailing the frequency at which their sensitive information was accessed by their apps.

The researchers found that app permission managers were helpful. When the participants were given access to AppOps, they collectively reviewed their app permissions 51 times and restricted 272 permissions on 76 distinct apps. Only one participant failed to review permissions.

Once the participants had set their preferences over the first few days, however, they stopped making changes. When they began getting the privacy nudges, however, they went back to their privacy settings and further restricted many of them. During this phase, which spanned eight days, users collectively reviewed permissions 69 times, blocking 122 additional permissions on 47 apps.

“App permission managers are better than nothing, but by themselves they aren’t sufficient,” Sadeh said. “Privacy nudges can play an important role in increasing awareness and in motivating people to review and adjust their privacy settings.”

Privacy researchers have struggled to find ways to motivate people to pay attention to online privacy, particularly for mobile devices that gather a great deal of personal information about the user. Sadeh said when people download an Android app, they are told what information the app is permitted to access, but few pay much attention, and fewer understand the implications of those permissions.

“The fact that users respond to privacy nudges indicate that they really care about privacy, but were just unaware of how much information was being collected about them,” Sadeh said.

The AppOps software was discontinued on later versions of Android. While iPhones do have a privacy manager, it does not tell users how often their information is used or for what purpose and does not nudge users to regularly review their settings.

Privacy nudges, however, are not a silver bullet either, Sadeh said. Given the new types and growing numbers of apps now in circulation, even the most diligent smartphone user is likely to be overwhelmed by the choices for privacy controls. Sadeh said ultimately, the solution may be personalized privacy assistants — software that learns an individual’s privacy preferences and selectively engages in dialogues with users to help semi-automatically configure many of their settings.

The release notes that research along these lines is progressing. Sadeh said his own research shows that it is possible to predict an individual’s mobile app privacy preferences with over 90 percent accuracy based on their answers to just a few privacy-related questions.

The study on app permission managers and privacy nudges was supported by the National Science Foundation, Google, Samsung, and the King Abdulaziz City for Science and Technology.