Humans are hard-wired to prefer experiences that end well, and the influence of previous experience declines the longer ago it happened. This means we can’t always trust that choices we make based on previous experience will serve our best interests in the future.

New research, published today in the Journal of Neuroscience, has revealed that two different parts of the brain are activated, and compete with each other, when we make decisions based on past experience. They can cause us to overvalue experiences that end well despite starting badly, and undervalue experiences that end badly despite starting well – even if both are equally valuable overall.