When we think of memory, we usually imagine it as a kind of mental photo album. It holds everything we’ve done, felt, and learned. Memory, we assume, is how we remember the past . But what if that’s not quite true? Some neuroscientists now believe that memory might not exist primarily to store the past, but to predict the future . According to this view, our brains use memory less like a history book and more like a simulation engine: constantly modeling what could happen next, so we can make better decisions. If this is right, then memory isn’t about where we’ve been. It’s about where we’re going. Memory as a Tool for Prediction Research in neuroscience and cognitive science has shown that the same parts of the brain that help us remember the past (especially the hippocampus) are active when we imagine the future . In fact, when people with damage to this area try to picture future events, they often struggle. They can’t visualize upcoming possibilities, even though nothing...