> To be truly radical is to make hope possible, not despair convincing^[Raymond Williams, Resources of Hope (published posthumously in 1989), p. 118] In his book, "From What Is to What If: Unleashing the Power of Imagination to Create the Future We Want", Rob Hopkins argues for the importance of hopeful thinking. His second chapter covers a lot of research on the effects of fear on the hippocampus. The hippocampus is involved with memory, but also with our ability to imagine the future. [[Donna Rose Addis]] is one of the leading researchers in this area. She tells Hopkins, "When we imagine a future event, we have to integrate details that may never have been integrated before. When you remember something, you are reintegrating details that already had linkages so it's not as demanding for the hippocampus." The hippocampus is packed with glucocorticoid receptors, and that makes it vulnerable to cortisol, a stress hormone. In small doses, cortisol is useful to break apart stored energy. High levels of cortisol, however, can damage cells in the hippocampus, reducing its size. Women who experience chronic stress in pregnany produce high cortisol levels that affect the hippocampus of their child. Researchers can also observe the hippocampus contract in response to fear. Gordon Turnbull, a specialist in PTSD, estimates that about half of Americans are suffering from some form of trauma. People who suffer from trauma are more likely to experience everyday events as more stressful, and negative futures come to mind more easily. They may even seek out information that confirms an increasingly pessimistic worldview. This vicious cycle causes more cortisol to be released, damaging the hippocampus even further.