When Paranormal Activity 3 chalked up record-setting numbers at last weekend's box office — its $54 million was the most ever for a horror film — experts in media psychology were not surprised. They say that distress and delight are correlated. "The pleasure comes from the relief that follows," said John Edward Campbell, assistant professor in the Department of Broadcasting, Telecommunications and Mass Media. "It provides a cathartic effect, offering you emotional release and escape from the real world of bills and mortgages and the economy and relationships."