A recent study by researchers at the University of Maryland predicted a person's score on a personality test to within 10 percentage points by using words posted on Facebook. Golbeck and her colleagues at the university's Human-Computer Interaction Lab surveyed the public profiles of nearly 300 Facebook users this year. They looked at users' descriptions of their favorite activities, TV shows, movies, music, books, quotes and membership in political organizations. They also looked at Facebook's Public "About Me" sections. The 300 participants then took a standard psychological exam that measures the "big five" personality traits: openness to experience, conscientiousness, extroversion, agreeableness and neuroticism ( 神经质 ). People who tested as extroverts on the personality test tended to have more Facebook friends, but their network were more sparse than those of neurotics, meaning that their friends were less likely to know one another than were the friends of other Facebook users. People who tested as neurotic had more "dense" networks of people who know one another and share similar interests. The researchers also found that people with long last names tended to be have more neurotic traits, perhaps because " a lifetime of having one's long last name misspelled may lead to a person expressing more anxiety and quickness to anger,” according to the study. People who tested high on the neurotic scale also tended to use a lot of anxiety-associated words, such as "worried", "fearful" and "nervous", on their facebook posts. They also use words describing eating: "pizza", "dish", "eat". Golbeck says she can't explain that last correlation. "You'd have to get a psychologist on that one," she said. "It could be that people that are neurotic talk more about what they are eating. It could be a deep correlation that we can't understand on the surface." Golbeck says that evaluating a person's personality is important to anticipating how well they will get along with others in school or a job. But some critics say that you can't really use social media to figure out human behavior.