UC Berkeley ran a study on fear several years back. The ad read something like, "Fear study, $20 an hour." Subjects showed up and an fMRI machine tracked which areas of the brain 'lit up' when shown scary things. The doc running the study noticed something strange. A lot of the subjects who showed up were carrying motorcycle helmets. And in nearly all of those subjects the pleasure center of the brain lit up when shown things that freaked the rest of the subjects out. And the things that would normally illicit pleasure didn't even register in the brains of these 'risk takers'.
The results didn't make much sense. How could people who literally received pleasure from things that will kill you even live long enough to reproduce? How was this biologically beneficial?
But sometimes what's bad for a single organism is good for the species. Ya see, without claws or fangs, success of the human race required a certain percentage of the population be highly intelligent, strategic-minded thinkers who were also wired for risk taking. Without 'em carrion, not Omaha Mammoth, is on the menu. And that Sabre Toothed Tiger, or bear, or pack of wolves makes a meal of your entire tribe while everyone plays 'pass the spear' and 'play dead in the corner'. So you see, you're only alive because of the ancestors of '.....' guys like Dunlop and McGuinness sought out to protect other humans for no other reason than the fact it was EXCITING. (If you've ever been thoroughly grateful that someone wants to fight, or ran towards a charging animal, you've got this gene.)
The ability to handle adversity can transfer into the less dangerous realms of personal and professional life, too, though. (Hey, more benefits!) The ability to manage emotions in difficult situations where indecision leads to death tends to make great leaders and persistent, decisive individuals who push humanity forward with technological or political or scientific advancements.
The problem with being wired to enjoy danger is, in a modern society (other than dying young) is there is little of it (danger). Without new continents to conquer, without perilous voyages into the unknown, without predators circling just outside the light of your campfire, life is quite simply devoid of meaning. The pleasures of a wife and kids, an espresso machine and a plump 401k leave you suffocating to death wondering why nothing is satisfying. As ironic as it is, 'suicidal' activities, for such people, provide the only reason to wake up in the morning.
