1.) In my opinion, the most important feature of the "HSS", or those who favor high risk situations, is there ability to process more information without reverting to the more primitive, instinctual human. This reduces the thrill they get from each activity, creating a boring life. These high-risk seekers often pair off with others like themselves, while those less inclined towards risk taking seek friends of a similar tendency.
3.) I think risk-takers, like rock climber Todd Wells, have a problem with the neurochemical explanations for their behavior because it destroys their very objective. They seek risks to escape from the restrictions placed upon them by society and to gain a greater perspective of themselves. However, when a scientist claims to be able to explain the motivation behind their behavior, they feel that the individuality of their method of escape is destroyed by society's scientific, structured explanation regarding their risk seeking.