A computer programme that analyses your Facebook 'Likes' may be a better judge of your personality than your close friends and family, according to a new study.
Using a new algorithm, researchers have calculated the average number of 'Likes' artificial intelligence (AI) needs to draw personality inferences about people as accurately as their partner or parents.
The study compared the ability of computers and people to make accurate judgements about our personalities.
The results show that by mining Facebook Likes, the computer model was able to predict a person's personality more accurately than most of their friends and family.
Given enough Likes to analyse, only a person's spouse rivalled the computer for accuracy of broad psychological traits.
Researchers at the University of Cambridge and Stanford University describe the finding as an "emphatic demonstration" of the capacity of computers to discover an individual's psychological traits through pure data analysis.
"In the future, computers could be able to infer our psychological traits and react accordingly, leading to the emergence of emotionally-intelligent and socially skilled machines," said lead author Wu Youyou, from Cambridge's Psychometrics Centre.
"In this context, the human-computer interactions depicted in science fiction films such as Her seem to be within our reach," said Wu.
Researchers said these results might raise concerns over privacy as such technology develops; the research team support policies giving users full control of their digital footprint.
In the study, a computer could more accurately predict the subject's personality than a work colleague by analysing just ten Likes; more than a friend or a cohabitant (roommate) with 70, a family member (parent, sibling) with 150, and a spouse with 300 Likes.
Given that an average Facebook user has about 227 Likes, the researchers said this kind of AI has the potential to know us better than our closest companions.
Researchers used a sample of 86,220 volunteers on Facebook who completed a 100-item personality questionnaire through the 'myPersonality' app, as well as providing access to their Likes.
These results provided self-reported personality scores for what are known in psychological practice as the 'big five' traits: openness, conscientiousness, extraversion, agreeableness and neuroticism.
Researchers could establish which Likes equated with higher levels of particular traits eg liking 'Salvador Dali' or 'meditation' showed a high degree of openness.
Users of the 'myPersonality' app were then given the option of inviting friends and family to judge the psychological traits of the user through a shorter version of the personality test.
The study was published in the journal PNAS.