Psychologists, criminologists, historians and those who are simply curious will expend a great deal of effort trying to find a common threat that links the perpetrators of spectacle crimes. Surely, there must be some relatively simple and indeed common element that connects Eric Harris, Seung-Hui Cho, Anders Brevik, Mohammed Atta, James Holmes, Adam Lanza, Jared Loughner and Tamerlan Tzarnaev; and indeed there is. Some of these were psychotic, some ideological, some reigious fanatics. There is a great deal of heterogeneity in the motives, and cognitive processing of these individuals, but there is one thing common to them all: fantasy. Each of theme had a fantastic notion of how his crime related to some goal, with such relationship reinforced not by rational analysis but by emotional compulsion.
It is assumed that each had a pathological lack of empathy, and this is true, but one of the things that fantasy provides is a mechianism that makes empathy unnecessary. Movie villains and video game characters can be killed wantonly without moral qualm because they are acknowledged to be only part of a fantasy. this mechanism also works the other way, however. Not only can reality be projected onto fantasy, but real people can be perceived as the characters in a fantastic episode, in which everything; the motive, the outcome, the emotional satisfaction, is ultimately a figment of imagination.