Do you prefer curly French fries over straight ones? If not, then you’re stupid, or at least you are if you happened to indicate this preference over on Facebook.

According to a recent study by Cambridge University that attempted to ‘guess’ people’s personalities based on their Facebook ‘likes’, those who publicly declared an affinity with curly fries have higher IQs than those who don’t.

The finding is just one of dozens of gems among a horde of data that shows, click-by-click, Facebook users are slowly but surely building up an extraordinarily revealing profile of themselves (never mind the fact that most people’s profiles aren’t even complete). The research was published by the Proceedings for the National Academy of Sciences, and details how all manner of traits – including personality, sexuality, gender, religious and political views – can be figured out with a high degree of accuracy simply by looking closely at someone’s Facebook ‘likes’.

Even more startling, is that all of the information used by researchers was found in the public domain, meaning that anyone could have worked this out.

For example, using the researcher’s algorithm, it’s possible to correctly guess a man’s sexual orientation 88% of the time just by looking at what movies and TV shows he ‘liked’. But interestingly, while gay men are fairly easy to spot, the study showed that very few of them – less than 5% – actually advertise that fact, avoiding clicking ‘like’ on posts or pages related to gay topics. Rather, it would seem that liking “Desperate Housewives” or “Britney Spears” is more of a giveaway.

The researchers could also tell if someone was a frequent drug user 65% of the time, while Muslims and Christians were correctly classified as such in 82% of cases, just by going on their publicly expressed preferences. Researchers could even derive more ambiguous details by designing ‘like’ predictors that can determine whether or not a Facebook user’s parents had separated while they were young.

The authors of the study said that their findings should serve as a warning to people who, for the most part, simply do not comprehend how much they’re giving away about themselves online. Of course, they freely admitted that this kind of data would be invaluable to advertisers looking for ways to improve their ad targeting, while fields of study such as psychology could also benefit from the data. But regardless of these ‘benefits’, more than anything else the study serves as a reminder of just how easy it is to gather data on people without their knowledge.

“One can imagine situations in which such predictions, even if incorrect, could pose  threat to an individual’s well-being, freedom or even their life,” conclude the researchers.

So perhaps now is a timely moment to remind readers that it is possible to change your privacy settings to keep your preference for curly French fries – or anything else – safely out of the public eye.