You are what you like - the app says so

The app cautions that it's a measure of how you display your personality online, and not of your personality itself. Photo / Getty Images

University’s technology uses Facebook to work out users’ personality and habits.

A vaguely disconcerting app from researchers at the University of Cambridge can guess how old you are, how smart you are and who you like to sleep with.

It's not magic, and it's not psychic. The tool, called "Apply Special Sauce", is based entirely on the pages you've "liked" on Facebook.

The app essentially works by comparing your "likes" with those of millions of other people. After you grant it access to your Facebook account, it sucks up the records of every page you've ever liked and runs that "digital footprint" against a vast internal model that Cambridge has built from tens of thousands of personality tests and six million social media profiles.

Based on how closely your likes do or do not adhere to that model, Apply Special Sauce can guess a lot of things about you - including your age, politics, sexual preference and level of intelligence. And while the app cautions that it's a measure of how you display your personality online, and not of your personality itself, I found that it was startlingly accurate: It got my gender, my job and my age right, within a year, and it accurately predicted my relationship status, sexual orientation and political and religious affiliations.

When researchers at Cambridge and Stanford published a paper on their model this year, they said it worked out personality better than real people did.

It's a good party trick, and a fun application of a technology that's grown quite trendy in recent months. But more than that, Apply Special Sauce is further proof that even the smallest, most casual signals we throw off into the digital ether don't disappear.

Research has already demonstrated, for instance, that these algorithms and models can accurately guess your sexuality from your Facebook likes.

So far, none of this has probably affected you - but that's changing. The Apply Special Sauce app exists largely to advertise Cambridge's technology to private companies, who could use it in market research, customer service and ad targeting.

More to the point, it's only one of many such services. Crystal, a new plug-in for Gmail, promises to analyse the personalities of people who email you and recommend ways to communicate better; IBM's Personality Insights tool will infer "cognitive and social characteristics", including psychological needs, from texts, tweets and forum posts that you feed it.

Whether any of these services can get your personality exactly "right" is anybody's guess. But you can try Apply Special Sauce yourself at applymagicsauce.com.