They say you can't judge a book by its cover, but a new study suggests a computer can accurately judge your personality by the things you "Like" on Facebook.

The computer's judgments aren't perfect, but they're often just as good at predicting our personality traits as our coworkers, roommates, friends or family members, according to a new study.

Only romantic partners are able to match the computer's personality-divining prowess, the authors of the study say. But while our spouse's knowledge of our personality has likely developed over years of dinners, phone calls and cohabitation, the computer program only needs a few seconds and a list of our Facebook Likes to come to the same conclusions.

"I would say that as humans, we are amazing at judging personalities," said Michal Krosinski, a psychologist who works at the Stanford University Computer Science Department and one of three authors on the study. "What is striking is that computers can beat us at our own game using a simple model and big data."

According to the computer model, people who like pages for "Snooki" and "BEER PONG" are more likely to be outgoing and active, while those who like "Doctor Who" and "Wikipedia" are more likely to be shy and reserved. Liking "the Bible" and "smiling" suggests a person is on the cooperative end of the spectrum, while those who like "Atheism" and "CHANEL" are more competitive.

"When you look at the results, there are some indicators that are very obvious, and others that we wouldn't have realized on our own," said Youyou Wu, the first author on the paper, who worked on this research as a PhD student at the Psychometrics Centre at the University of Cambridge. (She is now an intern at Facebook.)

The data from the study comes from the myPersonality project, a Facebook application designed by David Stillwell of the University of Cambridge. Between 2008 and 2012, 6 million myPersonality users agreed to take a lengthy psychometrics test in exchange for getting feedback about where they fall in the spectrum of the five big personality traits - openness, conscientiousness, extraversion, agreeableness and neuroticism.