People who think more about whether they are right have more cells in an area of the brain known as the frontal lobes.
By Katie Alcock, Science reporter, BBC News
UK scientists, writing in Science, looked at how brain size varied depending on how much people thought about decisions. But a nationwide survey recently found that some people think too much about life. These people have poorer memories, and they may also be depressed. The study is the first to show that there are physical differences between people with regards to how big this area is. These size differences relate to how much they think about their own decisions.