In bed with Google: A new Sleep Sensing feature prompts privacy worries

Google wants you to take its latest gadget with you into the bedroom. 

The marquee feature on the search giant's new Nest Hub, a smart display released on Tuesday, is a tool called Sleep Sensing that tracks a person's sleeping patterns by measuring motion and noise at their bedside. It can record when you fall asleep and wake up or how long it takes you to get to sleep. It knows if your slumber is interrupted during the night and how fast you're breathing while asleep. 

It's by no means the first sleep tracker to hit the market. But some privacy experts worry specifically about Google's push into sleep data because of the company's shaky track record when it comes to user privacy. The focus on sleep tracking underscores an uncomfortable reality about Google's size and ubiquity. The tech giant already collects vast amounts of data about people in their waking lives: what they search for online, what videos they watch on YouTube and where they've traveled, from location data gathered through an Android phone or Google Maps . Now the company is zeroing in on the other half of people's lives -- what they're doing when they're not awake. 

"Now Google's keeping tabs on the sleep habits of potentially a big fraction of the population," said Jennifer King, privacy and data policy fellow at the Stanford Institute for Human-Centered Artificial Intelligence. "It's their scale and scope that's so concerning."

Google is going to great lengths to try to get people to trust the device. An icon on the screen lets you know when the feature is on, and there's a physical switch on the device to turn off the microphone. Sleep Sensing is powered by a radar chip the company developed in house. The use of radar is partly meant to assuage privacy concerns, allowing the company to track movement without the presence of a camera. Raw audio and radar data is only processed locally on the device, while sleep-related summaries and insights are sent to Google servers.

The company is adamant that it won't use sleep data for personalized advertising. A Google spokeswoman said the data will be siloed off from the ads business. "The sleep data is stored separately from other Google user data that is accessible for use by the Google ads team," she said. 

Pressed further, she said aggregated data isn't separated in the same way. Google has no plans to use aggregated sleep data for advertising, she said.

'Not a reliable narrator'

Regulators are already worried about Google's access to health and biometric data. Google earlier this year said it closed a $2 billion deal to acquire Fitbit , the struggling fitness tracker pioneer, in an attempt to bolster Google's hardware operation. The buyout has sparked alarm among critics worried about Google's ability to strong-arm its way into new industries and buy the health data of millions of people. Google has said it also won't use Fitbit data for targeted ads. 

Sleep tracking has been around for years. Apple lets people measure sleep trends with their Apple Watch . Fitbit recorded sleep data long before Google bought it. Google, in fact, has offered sleep tracking features for years through its Google Fit app for Android phones . 

Google is offering its Sleep Sensing feature as a "free preview" until next year, hinting at a paid service to come. The company also said it's looking for ways to integrate the sleep data with Fitbit data. Fitbit has health partnerships with third parties, but the Google spokeswoman said user data won't be shared without express consent.

Despite Google's promises about how it won't use the data, people should be wary, considering the company's failure to protect people's personal information in the past, said John Davisson, senior counsel for the Electronic Privacy Information Center, or EPIC, a Washington, DC-based nonprofit. Two years ago, Google, along with Apple and Amazon , received blowback for giving third-party contractors access to people's voice recordings from smart speakers in order to improve their natural language software. 

Google has also been criticized for how it has treated other biometric data. Last April, two children from Illinois sued the search giant for allegedly collecting biometric data, including face scans, of millions of students through its software tools for classrooms. The children, who sued through their father, claimed the data collection violated the state's biometric privacy law, as well as COPPA, a federal law that requires sites to get parental consent when collecting personal information from users under 13 years old.

"We really shouldn't and can't take their claims on their privacy practices at face value," Davisson said when asked about the sleep tracking feature. "They're not a reliable narrator."

Beyond ads, King, the Stanford fellow, worries about what other insights the data might enable. If you wake up multiple times during the night, the company could potentially take into account when you've had a bad night's sleep and are more irritable. King also wonders if the device could track people having sex. 

"If it's meant to track you while in bed, well, what are some of the other things people do in bed besides sleep?" she said. If so, Google might be able to make other inferences by knowing intimate details about someone's sex life, she said.  

Asked if the device could know when people are having sex, Google said no. "Our algorithms were trained to classify whether people are in bed, asleep, awake, or restless, your breathing rate and whether there was a cough or a snore," the spokeswoman said. "They are not deducing intimacy, nor have we tried to use data from Nest Hub for that purpose."

Google says its motion features don't detect specific bodies or faces. Still, privacy experts laugh at the absurdity that this is the conversation we need to be having now. "It's a frontier we should not let them explore," EPIC's Davisson said.