Optimism bias is the belief that the future will be better, much better, than the past or present. And most of us display this bias. Neuroscientist Tali Sharot wants to know why: What is it about our brains that makes us overestimate the positive? She explores the question in her book The Optimism Bias: A Tour of the Irrationally Positive Brain.

In the book (and a 2011 TIME magazine cover story), she reviewed findings from both social science and neuroscience that point to an interesting conclusion: "our brains aren't just stamped by the past. They are constantly being shaped by the future." In her own work, she's interested in how our natural optimism actually shapes what we remember, and her interesting range of papers encompasses behavioral research (how likely we are to misremember major events) as well as medical findings -- like searching for the places in the brain where optimism lives. Sharot is a faculty member of the Department of Cognitive, Perceptual and Brain Sciences at University College London.