8. Negativity Bias

Let's face it: We live in a sensationalist society where scare tactics and negative headlines garner the most attention. If you doubt this for a minute, turn on your local news tonight. Scientists theorize that we perceive negative news to be more important than positive news. The risk-for the bears and for humans as a whole-is the tendency to dwell on bad news rather than embrace good news, and there's the added twist that the stock market is widely considered to be a leading indicator.

Read more: http://www.minyanville.com/special-features/random-thoughts/articles/12-Cognitive-Biases-that-Endanger-Investors/1/17/2013/id/47441?page=full#ixzz3uRslHrk0