University of Michigan Professor Brian Zikmund-Fisher explores this in the latest video from Risk Bites – at under 3 minutes long, it’s a fantastic introduction to why seemingly rational people sometimes behave the way they do toward vaccines.

According to Zikmund-Fisher, how we think about infectious diseases and risk is governed in part by the way our memories and feelings inform our perceptions – this is referred to by psychologists as the “availability heuristic”.  It turns out that when we try and figure out how rare or common a disease is, we try to think of people we have heard of who have had it.  If we know of people, we’re pre-programmed to feel more at risk than if we don’t.  And surprisingly, the statistics – the actual numbers of people who get sick – don’t seem to matter.

You can watch Brian’s video and others on the science behind human health risks at youtube.com/riskbites.  Brian can also be seen talking about risk, feelings and vaccines in the new NOVA documentary Vaccines – Calling The Shots, airing Wednesday September 10 at 9:30/8:30C.