Incognito browsing is not as private as most people think

Most people misunderstand this so-called privacy mode, new data show

You may think you’re going deep undercover when you set your web browser to incognito. But you’d likely be mistaken, a new study finds.

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You often can choose a private setting when you browse the internet. But be forewarned: It may not afford nearly as much privacy as you expect. That’s the finding of a new study.

Major web browsers, such as Google’s Chrome and Apple’s Safari, offer a private-browsing option. It’s sometimes referred to as “incognito.” This option lets you surf the internet through a private window. Normally, your internet browser saves a record into its history of each page that you visited. This option doesn’t. And what sites you visit won’t affect the suggestions your browser makes the next time you’re filling out an online form.

The way your browser normally tracks your activities on the web can make your life easier. It means you can get to your favorite websites more quickly. It means you may get to skip typing in passwords. But if you’re sharing a computer with other people, you might not want them to see such information. So incognito mode can help mask your past browsing history.

Many people believe — incorrectly — that the incognito setting protects them more broadly. Most believe that even after reading a web browser’s explanation of incognito mode.

For instance, a new study had 460 people read web browsers’ descriptions of private browsing. Each person read one of 13 descriptions. Then the participants answered questions about how private they thought their browsing would be while using this tool. (See some sample questions below in our quiz.)

The volunteers didn’t understand incognito mode, their answers now show. This was true no matter which browser explanation they had read.

The researchers reported their findings April 26 at the 2018 World Wide Web Conference in Lyon, France.

Mistaken assumptions

More than half of the volunteers, for instance, thought that if they logged into a Google account through a private window, Google wouldn’t keep a record of their search history. Not true. And about one in every four participants thought private browsing hid their device’s IP address. (This is the unique ID number that someone else can use to find out roughly where you are in the world.) That’s wrong, too. 

Blase Ur was one of the study’s authors. He’s an expert in computer security and privacy in Illinois at the University of Chicago. Companies could clear up this confusion by giving better explanations of incognito mode, his team says. For instance, the browsers should avoid vague, sweeping promises of anonymity. The web browser Opera, for instance, promises users that “your secrets are safe.” Nope. Firefox encourages users to “browse like no one’s watching.” In fact, someone might be.


Many people overestimate the privacy they get from using web browsers in incognito mode. How much do you know about private web browsing? See how you stack up against the study’s 460 participants.

H. Thompson; Source: Y. Wu et al/The Web Conference 2018

Maria Temming is the staff reporter for physical sciences, covering everything from chemistry to computer science and cosmology. She has bachelor's degrees in physics and English, and a master's in science writing.

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