Reluctance to abandon a strategy because we have invested heavily in it, even when a different course of action is clearly more beneficial.
Our aversion to losing makes us irrationally cling to the idea of regaining it, even though it has already been lost. This is why gamblers have trouble cutting their losses in the face of poor odds. Rationally speaking, the decision to travel onto an avalanche prone slope should only be influenced by conditions and consequences of the terrain, but we are irrationally wired to consider the time, effort, and money spent leading to that decision point. It’s a lot harder for Gerry to turn away from his objective if he just spent $500 on a hut trip or spent 8 hours approaching an objective, compared to an easy backyard objective.