My answer to Is it beneficial to have high expectations about one's own future?
Answer by Ken Larson:
We have all evolved as humans with an innate optimism. That optimism exists to a greater or lesser degree in us all.
The human mind has a terrific tendency to forget bad news and remember exactly the specific details of good news. That is so often the case with historical fact.
The 6 June 2011 – Time Magazine Cover Article, "The Optimism Bias" by Tali Sharot is very revealing in this regard. Here are the concluding paragraphs:
"The Puzzle of Optimism
While the past few years have seen important advances in the neuroscience of optimism, one enduring puzzle remained. How is it that people maintain this rosy bias even when information challenging our upbeat forecasts is so readily available? Only recently have we been able to decipher this mystery, by scanning the brains of people as they process both positive and negative information about the future. The findings are striking: when people learn, their neurons faithfully encode desirable information that can enhance optimism but fail at incorporating unexpectedly undesirable information. When we hear a success story like Mark Zuckerberg's, our brains take note of the possibility that we too may become immensely rich one day. But hearing that the odds of divorce are almost 1 in 2 tends not to make us think that our own marriages may be destined to fail.
Why would our brains be wired in this way? It is tempting to speculate that optimism was selected by evolution precisely because, on balance, positive expectations enhance the odds of survival. Research findings that optimists live longer and are healthier, plus the fact that most humans display optimistic biases — and emerging data that optimism is linked to specific genes — all strongly support this hypothesis. Yet optimism is also irrational and can lead to unwanted outcomes. The question then is, How can we remain hopeful — benefiting from the fruits of optimism — while at the same time guarding ourselves from its pitfalls?
I believe knowledge is key. We are not born with an innate understanding of our biases. The brain's illusions have to be identified by careful scientific observation and controlled experiments and then communicated to the rest of us. Once we are made aware of our optimistic illusions, we can act to protect ourselves. The good news is that awareness rarely shatters the illusion. The glass remains half full. It is possible, then, to strike a balance, to believe we will stay healthy, but get medical insurance anyway; to be certain the sun will shine, but grab an umbrella on our way out — just in case."