Deep Survival: Who Lives, Who Dies, and Why

Throughout Deep Survival, Gonzales raises the sticky question of bias in people’s perception and decision-making. He argues that bias plays an overlooked but highly consequential role in creating accidents and emergencies. This theme challenges the reader to consider how they may be putting themselves in danger in a survival situation.

Humans subconsciously project their memories into their plans and expectations for the future, which the author calls “mental models.” Gonzales reveals how people who are overly reliant on their mental models can become deluded and argues that the subconscious nature of this phenomenon makes it a common danger for outdoor adventurers. While people may think their plans are based on knowledge or preparation, Gonzales argues people instinctively base their mental models on conscious or unconscious memories. For instance, rock climbers may judge a certain climb as easy or enjoyable based on similar climbs they’ve previously completed, even if they logically know that the conditions could be very different for their next adventure. Developing mental models is an inherent part of human brain function, since people have evolved to make detailed plans for the future, which they store in the hippocampus. Gonzales argues that storing plans alongside memory intertwines the two, and that people often tie emotion to memory, which may make people feel invested in their mental models and want to execute them. He explains, “Plans are stored in the memory just as past events are. To the brain, the future is as real as the past” (84).

While mental models can be a hugely beneficial tool for people’s survival, such as Callahan’s well-designed boat and life bag system, they can be hazardous if people are unaware of the biases they create. Because of the emotional attachment to their plans, people may interpret new information as confirmation of their mental models, and “[t]he difficulty begins when reality doesn’t match the plan” (84). For instance, the four climbers at Yosemite felt very invested in their mental model of their day since they had driven a long distance, camped overnight, and were excited to tackle a particular ascent. As a result, they overlooked dangers even when they had the opportunity to notice them; they ignored the fact that they were behind schedule, did not have an accurate weather forecast, and were not dressed for stormy conditions.

Similarly, hiker Ken Killip became overly reliant on his own mental model of his hike in the Rockies. Rather than admit that he had lost his hiking companion and retrace his steps, Killip deluded himself into believing that he could reach Rock Lake, his intended destination, on his own. The author explains, “The perception that he was climbing Mt. Ida gave a more settled feeling to the area of his brain that was trying to create a mental map” (153). Even after an uncomfortable night on the mountain, Killip’s investment in his initial expectations continued to overpower his logical brain, and he “felt that he could not simply leave York and spoil the trip. York would be thinking: What a nitwit. And anyways, Killip didn’t quite believe that he was lost” (159). Killip did not begin to think like a survivor until he overcame the rigid bias of his initial mental model, opened his mind to new information, and “created a mental map of where he was, not where he wanted to be” (169).

Humans make mental models subconsciously, and they can be very valuable, so Gonzales does not advise against them. Instead, he suggests making flexible plans and staying open to new information. Gonzales repeatedly claims that survivors succeed because they are “open to the changing nature of their environment” and integrate new information into their plans (80).