Risky behaviour has been much in the news over the last few months in the context of the imprudent activities of banks and financiers alike. Current media reaction to the Swine Flu outbreak gives us a different take on how we perceive and respond to risk but based on the same febrile reporting. Over the last few days news broadcasts have devoted up to 50% of their time to coverage of the outbreak. Making the assumption that this reflects public concern (and not just journalistic ambulance chasing), what do we learn about how we perceive such threats?

I was first struck by the perversity of human reactions to risk way back in the 70s, when Kahneman and Tversky were conducting their gambling experiments, showing amongst other things just how bad humans are at using probability information to judge risk. They identified a number of cognitive short cuts or heuristics that people use in place of logic; for example the availability heuristic – how easily can a threat be brought to mind, how vivid is it? Fundamentally any risk assessment serves the purpose of driving our threat avoidance behaviour. This particular bias means that information or ‘news’ that feeds our fevered imaginations is likely to inflate our personal assessment of threat.

But back to Swine Flu; our inaccuracy in assessing true risk comes in large part from our ignoring prevalence as a key factor in assessing a threat. Ignoring or underplaying prevalence is why we are scared of shark attack (also pretty vivid!) and blasé in response to much more prevalent threats such as obesity. Put this all together and the faulty logic goes something like this:

‘People coming back from Mexico have Swine Fever: ergo, if you go to Mexico you will get Swine Fever!’ (Not – ‘a very very few people coming back from Mexico….' etc)

In reality the chances of becoming infected in Mexico must be many thousands to one against. You probably have a higher chance of being knocked down by a car in Mexico!

Now I, like you, am extremely glad that health professionals are advocating a proportionate response to the actual threat as it is currently understood. We will know that our biases have been fully triggered when we and the politicians start to respond to the perceived threat; the wearing of face masks and queues for vaccine will be pretty good indicators and you can bet that fevered reporters will be quick to let us know!

Trouble is I am just as prone to these biases as everyone else; so, Cancun for a cheap holiday? Probably not….what about you?