Researchers from the Pennsylvania State University found that they were not really thinking at all while posting private pictures or information, or at least were not thinking like most adults do.

What our model suggests is that teenagers do not think this way - they disclose and then evaluate the consequences.

"Adults often find this very difficult to understand and paradoxical because they are so used to considering possible risks of disclosing information online first and then taking the necessary precautions, based on those concerns," said Haiyan Jia, post-doctoral scholar in information sciences and technology.

"The process is more experiential in nature for teenagers," Jia added.

For the study, the researchers used data from the Pew Research Centre's 2012 "Teens and Privacy Management Survey".

The survey gathered information on social media behaviours from 588 teenagers in the US, most of whom were active users of sites such as Facebook.

Teenagers are often more exposed to online risks because they are using social media as a platform for self-expression and as a way to gain acceptance from their peers. When teenagers begin to struggle with privacy concerns, they often try to find possible protective actions to mitigate risk.

Those remedies include seeking advice from adults, removing online information or going offline completely.

"A parent's first impulse may be to forbid internet or social media access, but completely avoiding risks may cause other problems," according to researchers, who presented their findings at the "computer-supported cooperative work and social computing" conference on March 17.