18 Hardwired for Hope? I would have liked to tell you that my work on optimism grew out of a keen interest in the positive side of human nature. The reality is that I stumbled onto the brain's innate optimism by accident. After living through Sept. 11, 2001, in New York City, I had set out to investigate people's memories of the terrorist attacks. I was intrigued by the fact that people felt their memories were as accurate as a videotape, while often they were filled with errors. A survey conducted around the country showed that 11 months after the attacks, individuals' recollections of their experience that day were consistent with their initial accounts (given in September 2011) only 63% of the time. They were also poor at remembering details of the event, such as the names of the airline carriers. Where did these mistakes in memory come from? Scientists who study memory proposed an intriguing answer: memories are susceptible to inaccuracies partly because the neural system responsible for remembering episodes from our past might not have evolved for memory alone. Rather, the core function of the memory system could in fact be to imagine the future — to enable us to prepare for what has yet to come. The system is not designed to perfectly replay past events, the researchers claimed. It is designed to flexibly construct future scenarios in our minds. As a result, memory also ends up being a reconstructive process, and occasionally, details are deleted and others inserted. To test this, I decided to record the brain activity of volunteers while they imagined future events — not events on the scale of 9/11, but events in their everyday lives — and compare those results with the pattern I observed when the same individuals recalled past events. But something unexpected occurred. Once people started imagining the future, even the most banal life events seemed to take a dramatic turn for the better. Mundane scenes brightened with upbeat details as if polished by a Holly