Why does grief hurt so much? Why does death, the permanent absence of a person with whom you are bonded, result in such devastating feelings and lead to behavior and beliefs that are inexplicable, even to the grieving person? Neuroscience and cognitive psychology can provide some answers beyond what grief feels like—tackling the questions of why. Some of the answers to our questions about grief can be found in the brain, the seat of our thoughts and feelings, motivations, and behaviors. By looking at grief from the perspective of the brain, we will discuss the contemporary neuroscience of how bonded relationships are encoded in order to better understand the why of grief. Considering grieving to be a form of learning is helpful to understanding the trajectory of adaptation during bereavement.