Anxiety, especially for women, works against the procedure of arousal. There have been studies in which men and women were set into fMRI machines and requested to masturbate to orgasm," Kerner described. What was interesting, taking a look at the female brain versus the male brain, was that the more the girl got aroused, the more elements of the brain which were associated with tension and anxiety dimmed and deactivated." Girls reach an almost trance like state when they approach climax, however they are only able to get to that stage if they could turn off specific parts of their brain. As a result, if they are focused on reaching some sort of target during sex, that can create stress that works against the process of arousal.