Tally Sherritt is a cognitive neuroscientist at University College London. She believes in the optimism bias, and she believes it is rooted in neuroscience. Her experiments have repeatedly shown that the brain tends to process positive information about the future more readily than negative information. It's easy to see how that could feed the planning fallacy. If we think everything's going to be okay or better than what we anticipate, we might not take precautionary action.