Researchers at Carnegie Mellon University have found that the appearance of website has a big effect on how honestly people answer personal questions put to them by the site. But paradoxically, it turns out we’re more likely to spill our secrets on websites that appear less reputable. The way a website phrases questions also affects our willingness to disclose revealing information, the researchers found.

The findings could have implications for privacy online–affecting how marketers approach consumers, and how policymakers try to protect consumers from privacy abuses.

Companies are constantly collecting information about people online: Google stores billions of search queries every day, and Facebook tracks the interests and social habits of millions of users. Much of the information collected online comes from tracking how people behave, but some is volunteered willingly.

The Carnegie Mellon researchers designed several tests to determine what encourages people to give out personal information online. “We’re interested in particular in the dichotomy between what people say they desire in terms of privacy, and what we all actually end up doing online,” says Alessandro Acquisti, an associate professor of information technology and public policy at Carnegie Mellon. Acquisti was involved in the work along with doctoral candidate Leslie John and economics professor George Loewenstein.

In work to be published in the Journal of Consumer Research, the researchers asked volunteers an identical set of personal questions using three different-looking websites. The questions included “Have you ever ‘cheated’ while in a relationship?” and “Have you ever driven when you were pretty sure you were over the legal blood alcohol level?”

One site displayed an official-looking logo, formal fonts, and staid colors. Another site was designed to appear neutral. And the third used lurid colors, less professional-looking fonts, and a cartoonish devil icon. The researchers found that people were nearly twice as likely to admit to having engaged in “illicit” or “socially questionable” activities when presented with questions on the third site–the least reputable-looking one. About a third of all participants also gave up their e-mail addresses, and about half of those e-mail addresses were easy to trace back to the person’s real identity.