Posted on July 28, 2015

When Computers Assess Personality Better Than We Do

Robert M. Sapolsky, Wall Street Journal, July 22, 2015


Two papers–published in 2013 and early this year by Michal Kosinski of Stanford, David Stillwell of the University of Cambridge and colleagues in the Proceedings of the National Academy of Sciences–may provide an answer. And it should further deflate our self-esteem.

The first study involved more than 58,000 active users of Facebook. Subjects provided demographic information about themselves and took a standard test to classify their personalities in five broad categories: degree of openness, conscientiousness, extroversion, agreeableness and neuroticism.

The researchers then correlated the personality profiles with each person’s Facebook “likes,” an average of 227 per subject. Humans can readily detect links between a few likes and certain sorts of people–“Hey, have you noticed how this personality type is associated with liking poetry and Klingon opera?”

The computer did all this on a massive scale, comparing the nuances of personality and demographics with the Facebook likes of tens of thousands of people. From this came a mighty impressive computer model: Using the data from Facebook, it could predict a person’s race with 95% accuracy and gender with 93%. The model also accurately predicted sexual, religious and political orientation; intelligence; the likelihood of substance abuse; and personality according to the profiles from the five-category test.

How accurate is the computer model as compared with humans? Another 86,220 subjects took the personality test; the subjects’ friends and family then filled out a short personality-profile questionnaire about them. The researchers wanted to find out how many Facebook likes the computer needed before it could make a more precise personality assessment than the people closest to someone.

With just 10 random Facebook likes, the computer could beat an individual’s co-workers in predicting personality. With 70 likes, the machine trumped friends. With 150 likes, it crushed relatives. At 300 likes, the computer was better than a spouse. The authors titled their recent paper, “Computer-based Personality Judgments Are More Accurate Than Those Made by Humans.” Turncoats.