The psychologist responsible for the Stanford Prison Experiment claims that men are undergoing a crisis of masculinity as a result of pornography and video game use.
Psychologist and professor emeritus at Stanford University Philip Zimbardo discussed his research into the lives of 20,000 young men, and their relationship with pornography and video games in an interview on the BBC World Service.
Zimbardo said: "Our focus is on young men who play video games to excess, and do it in social isolation – they are alone in their room.
"Now, with freely available pornography, which is unique in history, they are combining playing video games, and as a break, watching on average, two hours of pornography a week.
He said that his research uncovered a "crisis" among young men, many of whom lacked the motivation a father figure can provide and instead took refuge in video games and pornography, to which they were forming damaging addictions.
Zimbardo describes his finding in his new book 'Man (Dis)connected: How Technology has Sabotaged What It Means to Be Male', in which he warns that excessive videogame and online pornography consumption changes brain structure.
The excessive use of the stimuli, he said, "begins to change brain function. It begins to change the reward centre of the brain, and produces a kind of excitement and addiction."
In an interview Guardian, he said that increasingly boys were being brought up in single parent households with no father figure.
"Fathers give love provisionally. If you want your allowance, if you don't want me to turn off your computer, then you've got to perform. That's always been the deal with fathers and sons – you don't get a pass just because you exist, just because you got my name on your birth certificate. You're going to do it because you want your father to love you and admire you. That central source of extrinsic motivation is gone now for almost one out of every two kids," said Zimbardo.
He warned that the lack of positive male role models in US media could exacerbate the problem, and that men should set up mentoring groups for boys and schools do more to provide boys with positive activities and outlets.
Zimbardo is best known for the Stanford Prison Experiment in the 1970s, in which students playing 'jailers' behaved with increasing brutality to students playing 'prisoners', exposing the dangers of access to unrestrained power over other human beings.