Thompson has rejected arguments that such video games are protected by freedom of expression, saying, "Murder simulators are not constitutionally protected speech. They're not even speech. They're dangerous physical appliances that teach a kid how to kill efficiently and to love it," as well as simply calling video games "mental masturbation". In addition, he has attributed part of the impetus for violent games to the military, saying that it was looking "for a way to disconnect in the soldier's mind the physical act of pulling the trigger from the awful reality that a life may end". Thompson further claims that some of these games are based on military training and simulation technologies, such as those being developed at the Institute for Creative Technologies, which, he suggests, were created by the Department of Defense to help overcome soldiers' inhibition to kill. He also claims that the PlayStation 2's DualShock controller "gives you a pleasurable buzz back into your hands with each kill. This is operant conditioning, behavior modification right out of B. F. Skinner's laboratory."