Reading is good for you. There is increasing evidence to show that reading isn't merely a way of improving literacy and knowledge, but that it might actually be good for one's mental and physical health, too. In the age of Twitter and short attention spans, reading novels, which requires intense concentration over a long period of time, could be the antidote . Neuroscientists Baroness Susan Greenfield says that reading helps to lengthen attention spans in children and improve their ability to think clearly. "Stories have a structure that encourages our brain to think in sequence, to link cause, effect and significance," she says "It is essential to learn this skill as a small child." "In a computer game, you might rescue a princess, but you don't care about her, you just want to win," she explains, "But a princess in a book has a past, present and future. You can relate to her. You see the world through her eyes" According to professor John Stein, Oxford university, reading is far from a passive activity. "Reading exercises the whole brain," he explains. " When we get lost in a good book, we are doing more than following a story, Imaging what is happening is as good as activating the brain as doing it. In other words, our brains simulate  real experiences, and it is just as if we were experiencing them ourselves. This doesn't happen when we are watching a TV or playing computer games." Getting stuck in a good novel appears to be good for one's mental health. Reading helps one not only fights loneliness, but also forget one's own problems for a while. Researchers found that just six minutes of reading could reduce stress levels by more than two-thirds, more than listening to music or going out for a walk. The concentration required to read distracts the mind, easing muscle's tension and slowing the heart rate. Reading may be good for physical health, too, by preventing brain aging and disease. What is the main purpose of this passage?
To show how to improve children's attention spans To encourage people to read To show that Twitter has a negative influence To compare the results of reading and watching TV