When it comes to giving away personal data – whether to retailers, at the doctor's office, or on social media sites – Americans are most concerned about sharing information that exposes their whereabouts.

In fact, people tend to be uneasy about sharing location data with auto insurers for tracking locations and driving histories or with tech companies that can monitor behavior and movement inside homes, according to a Pew Research Center study released Thursday.

"People’s homes and their cars feel like privacy sanctuaries to them," said Lee Rainie, director of Internet, science, and technology research at Pew. "The people who were not keen on these bargains were people who did not want to be monitored in those spaces or felt really uncomfortable."

The Pew study is the first of its kind to gauge consumers' feelings around data sharing and comes on the heels of other surveys from the group that reveal a growing consumer wariness about how the government and corporations are using personal data.

The study released Thursday polled 461 American adults to gauge where peoples' comfort levels with various scenarios in which their data is typically captured, such as office surveillance cameras with facial recognition technology, store loyalty cards, health information sharing, free social media accounts, and smart thermostats.

The survey asked specifically about how participants felt about insurance company placing devices in their cars to track speed and location so that motorists could earn discounts based on driving performance. Just 37 percent said they felt comfortable with that scenario.

Another question focused on smart thermostats that track movement to optimize temperature, thus saving money on energy. Only 27 percent said they would be willing to test the smart thermostat.

"Location information for some people really feels pretty important and pretty special and worth protecting,” said Mr. Rainie.

Several factors influenced people’s decisions for sharing information. Often, participants expressed hesitation to share data because of concerns of hackers or that companies would profile them in order to send targeted ads. Also, many indicated they were worried data would be used in ways other than the stated purpose.

"Some of the marketing tracking things are creepy," said one participant. “I look at one thing online and then see it on every single site for weeks. At first – intriguing. Then creepy.”

Around 17 to 20 percent of participants for each scenario said they'd feel comfortable sharing data depending on the details of how the information is used.

"There was this really interesting realization sometimes for people that a lot of their day was given over to this kind of bargain – 'I’m being asked for this information. My personal information is being captured, and I’m potentially getting a benefit for it,' " said Rainie.

The study is one of several the Pew has conducted on privacy over the past two years. Previous reports found that Americans feel like they don’t have control over the collection of their data, and they don’t have much faith that those collecting their data – governments and private companies – can adequately protect it.

Going forward, Rainie said, he would like to get a better sense of why people share information in the first place, and what they’re getting out of it.