What is Roberts saying about friendship on Everest? To what extent is this quote true based on chapters 11–15 of Into Thin Air? "How much of the appeal of mountaineering lies in its simplification of interpersonal relationships, its reduction of friendship to smooth interaction (like war), its substitution of an Other (the mountain, the challenge) for the relationship itself?" Support or refute using at least one specific example from these chapters.

Of course, you can take this answer in either direction. But if you take into account already the very beginnings of chapter 11, you can easily support Roberts’s claim that mountaineering reduces friendships.
Under severe, sometimes life-threatening circumstances, such as the mountaineering in Into Thin Air, people quickly show their true character, as most of their actions are often done in a hurry, even on impulse. An instance of such a reaction would be Fischer yelling at Boukreev for neglecting his duty of keeping a watchful eye on his clients (chapter 11). Here Fischer, though completely understandably, quickly loses his temper and is ignoring any kind of friendship that may exist between the two.
Later in the chapter, something completely opposite happens; after learning of Chen Yu-Nan’s death, Makalu Gau shows an utter lack of emotions and orders his team to continue the climb.
By observing these reactions to some stressful moments during the mountaineers’ climb to Everest, we can draw a conclusion that in burdensome situations, we, as people, are very quick to impulsively react. In this sense, Roberts’s claim poses an interesting and thought-provoking look at human relations.