Attention Facebook users: Do you "like" Mozart, science, "The Colbert Report" and curly fries? Chances are, you've got a high IQ. Have you clicked the thumbs-up icon for Tyler Perry, Harley Davidson and Lady Antebellum? Perhaps you're not quite as cerebral.
What you endorse on the popular social media website may say a whole lot more about you than you intended, researchers from the University of Cambridge in Britain have found.
You may not think twice about your fondness for NASCAR, "The Bachelor" and Oklahoma State University, but those affirmations fit the pattern of a person who's conservative and less open to new things, they reported this week in Proceedings of the National Academy of Sciences.
Even traits that users of social networks may not want to broadcast - including smoking behavior, drug use or sexuality - can be sussed out pretty accurately by their patterns of likes, the researchers found after combing through data from 58,466 Facebook members in the U.S. More than a quarter of regular Facebook users click the like button for content they find there.
The study's conclusions may send marketers deeper into the data mine and prompt some of Facebook's billion monthly users to adjust their privacy settings.
Others may just scratch their heads. In the report, the researchers acknowledged that "There is no obvious connection between curly fries and high intelligence."
"We haven't come up with a reason," said David Stillwell, who manages Cambridge's psychometrics center, which analyzed the Facebook data.
The link between curly fries and intelligence may just be "statistical noise," Stillwell said. "The question is, do you know what your likes are saying about you?"
To find out how revealing the likes were, Stillwell and his colleagues invited Facebook users in the U.S. to take online personality and intelligence tests. One-third of those they invited agreed to let the researchers see their results and all their profile information and "likes."
The study authors then crunched the numbers to see which sets of likes were predictive of personal traits.
Some of the results were hardly surprising. Likes could accurately predict a user's gender and ethnicity in 95 percent of the cases, Democrats and Republicans could be identified 85 percent of the time, and Christians and Muslims were sorted correctly 82 percent of the time.
On the other hand, accurately predicting whether your parents split up before you were 21 was only slightly better than chance: 60 percent.
But even doing better than a coin flip was significant, researchers noted, because it required the algorithm to glean something about people related to the user, not about the user himself.
The capability to infer such attributes, including personality traits, surprised some experts in the psychometrics field.
"I think it's an intriguing result that you can make these predictions, especially on personality," said Michael Walton Macy, a Cornell University sociologist who has produced similar results from other publicly available data.
Facebook likes, in fact, are almost as informative as commonly used questions in personality tests when it comes to assessing someone's openness to new experiences and ideas, according to the study. On that score, fans of Hello Kitty tended to score high on the openness scale but lower on the conscientiousness scale.
Some Facebook users might come to regret their endorsements. A thumbs-up click for Terry Pratchett, a British fantasy novel writer, could indicate you're an introvert, Stillwell said. "If an employer saw it, what would they know about you?" he said.
Similarly, a man may not realize that liking Kathy Griffin and the musical "Wicked" could signal to others that he is gay. Men who liked professional wrestling were more likely to be straight. A person who likes the metal band Slayer and the sporting goods brand Under Armour could be a smoker, the study found.
Among the more poignant insights was the apparent preoccupation of children of divorce with relationship issues. For example, those who expressed support for statements such as "Never Apologize For What You Feel It's Like Saying Sorry For Being Real" or "I'm The Type Of Girl Who Can Be So Hurt But Still Look At You & Smile" were slightly more likely to have seen their parents split before their 21st birthday.
The accessibility and use of information on Facebook has been a perennial concern, sparking petition campaigns and lawsuits aimed at enhancing safeguards for privacy.
"Your political party, mortgage and even your parents' marital status is online," said Dr. Nicholas Christakis, a physician and social scientist who directs the Human Nature Lab at Harvard University. "I think this paper is alarmist. We can go from curly fries to pogroms in a couple steps."
This report includes information from The Associated Press.