Confirmation bias is one of the reasons why two people can see the same event in a radically different way. Simply put, it is the process by which each of us filters our environment in such a way that it tends to confirm our world view. Broadly speaking, if you have, say, a pessimistic view of the world around you (that, for example, it's dangerous), then you will quite naturally hone in on information that confirms this view. You will see the headline about the terrorist threat, and 'filter out' the larger headline about good economic growth.

We all do it and the only way to mitigate against it is to monitor yourself and ask questions, constantly. Of course, that is hard work and it is easier to leap straight back into the breach, where well-worn mental threads bind you to a way of thinking and acting. Confirmation bias happens on both a macro and micro level. It is just as relevant to the person who seeks out information about their unpopularity at the office party, in spite of evidence to the contrary, to the person who scans the headlines or the news aggregators. We select data in and select it out to reflect our own biases and to confirm what we already know about ourselves and the world. Trouble is that what we know is often inaccurate or self-defeating.

Being a cautious optimist myself, I remain hopeful of good news in most situations. But I suffer from confirmation bias like everyone else. I try hard to see the good in the world, but the overwhelming narrative of war, atrocity, barbarity, drugs, pornography and human insufficiency is powerful. Yes, there is a media bias towards bad, sensational or disturbing news, undoubtedly, which I factor in. It is hard, in a 24/7 information-saturated climate, to find a reasonable and rational middle path. And yet, it is possible.