Decision-making among family members in the intensive care unit fundamentally diverges from a rational deliberation process. This is due to cognitive barriers to complex decision-making under conditions of uncertainty and stress, leading decision-makers to rely on heuristics and biases that can lead to value misaligned decisions. The difficulties surrogate decision-makers encounter while engaging in shared decision-making and the value-misaligned decisions that they make when selecting treatment or care options are not personal shortcomings, but rather predictable and systematic intricacies of human behavior. In this chapter, we explore heuristics and biases that may influence decision-making in the intensive care unit and explore ways to minimize their undesired effects on decision-making during critical illness.