Hugh Pickens writes "Drawing on cognitive science, an increasing number of game theorists and designers say that our growing love of video games has important things to tell us about our intrinsic desires and motivations. Central to it all is a simple theory – that games are fun because they teach us interesting things and they do it in a way that our brains prefer – through systems and puzzles. 'With games, learning is the drug,' writes Raph Koster, the designer of seminal multiplayer fantasy games such as Ultima Online and Star Wars Galaxies. 'In game theory, this is often spoken of as the "magic circle": you enter into a realm where the rules of the real world don't apply – and typically being judged on success and failure is part of the real world. People need to feel free to try things and to learn without being judged or penalised.' Another important element is autonomy as games tap into our need to have control. This is very obvious in 'god games' such as The Sims, where we shape the lives of virtual humans, but it's becoming a vital element of action adventures and shooters, too. Finally another important game design facet is 'disproportionate feedback,' in which players are hugely rewarded for achieving very simple tasks. In highly successful shooters such as Call of Duty and Bulletstorm, when an enemy is shot, they don't just collapse to the floor, they explode into chunks. 'You're good, you're a success – you're powerful,' writes Stuart. 'Disproportionate feedback is an endorphin come-on.'"