What makes some people want to base jump off a building, or climb a cliff with no ropes? A thrill-seeking personality may be necessary, but is it enough to court the sort of danger that could kill? In this week's Why Factor, we explore why some people risk death in pursuit of adventure. CONTRIBUTORS Hazel Findlay, Professional climber. Erik Monasterio, consultant in Forensic Psychiatry, clinical director of the regional forensic service in Canterbury New Zealand and senior clinical lecturer with the University of Otago. Mary Philips, Professor in Psychiatry in chemical and translational science, University of Pittsburgh Medical Center. Tim Woodman, Professor of Psychology, School of Sport Health and Life Sciences at Bangor University. Roberta Mancino, BASE jumper and stunt woman. Rob Fletcher, associate professor of sociology of development and change at Hanagen University in the Netherlands. Steven Lyng, Professor emeritus at Carthage College and Kenosha Wisconsin. Photo: Male climber gripping on handhold while climbing in cave Credit: Getty Images