What have we learned since the H1N1 scare took hold over the last several months?

Now that the incidence rate of the disease is steadily decreasing, looking back it seems that our collective fears outweighed the extant danger. I think that there is an important message here, namely, that we as individuals or as a society often miss the mark when it comes to perceiving danger. Psychologists use the term heuristics or aids in learning, in this case erroneous heuristics, to examine our biases when it comes to seeing danger. Let me review two of these biases in regard to the H1N1 scare.

#1 Bias; Discounting the Habitual.

As humans, we have heightened sensitivity to novel events, particularly those drenched in threat. Luckily though, as our bodies would not survive in a constant state of high alert, we adapt. Soon, constant exposure to a particular stimulus gradually becomes just another piece of the cognitive puzzle in our world of tonic stimulation. Our ability to discount recurrent bombardments of stimuli may be problematic however, when dealing with events laced with danger, as we tend to also habituate to their level of associated threat.

In my home province of Quebec, fifteen people will die today as a result of downplaying threat. In fact, 15 people died yesterday, the day before and throughout the year yielding a total of over 6500 annual deaths directly attributable to the particular threat of smoking. I don’t believe that any newspaper, TV station or any media outlet led their reporting with this fact. One could only image the media attention if 15 people per day were to die of global warming or radiation poisoning from the tailings of an uranium mine. Tobacco-related deaths are simply not news anymore, but smoking remains a significant and real danger.

#2 Bias; Small sample sizes.

Ask people to simulate the heads or tails outcome of a random coin toss and what never appears in their guesses is a four, or even three sequence head or tail repetition. What these guessers invariably reproduce is a pseudo-random sequence where such repeated outcomes are deliberately avoided. However, this is not so in real life as a sequence of three consecutive heads can easily occur despite the fact that over a large sample, say 1000 coin flips, heads and tails occur almost equally.

Returning to our perception of danger, when we limit our view to small samples – small with respect to a historical time period we fall subject to this bias. In contrast, if we expand the time horizon just a little, say going back a mere 150 years, a more accurate perception of danger can be obtained.

To illustrate my point, let’s expand our historical time machine to example New York city in 1865. Our guide will be Professor Alison Aleiloe and colleagues writing in the American Journal of Infection Control, 2006 describing New York in the following terms:

In the early part of the 1800s, the U.S. fared no better than Europe. Both rural and city dwellers lived in a world of filth. Animal wastes were everywhere on farms, causing boots and clothing to be covered by manure. City streets were used for disposal of food wastes and dishwater, as well as being covered with horse manure. In most cities, free-roaming animals, often pigs, scavenged the garbage, which kept the streets freer of garbage but spread animal waste

The authors go on to describe the disease consequences of living in this urban filth:

In history, it appears that disease and death were so common that only the dramatic plagues and pestilences made an impression on the early writers. This might be the first lesson about our past:

From time immemorial until well into the 19th century, infectious disease epidemics exacted their toll from everyone in every nation -rich and poor, saint and sinner, and city dweller and farmer

Describing the regular epidemics of typhoid, yellow fever, small pox and cholera, the authors then go on to describe the years between epidemics:

In these days, even the “good years,” when there were no remarkable disasters, were still disasters by today’s standards.

The Bottom Line

So, our few cases of H1N1 deaths pale in comparison to what some of our grandparents might have lived through not that long ago. In relation to historical infectious disease trends, the H1N1 pandemic illustrates threat embellishment. On its own, dangers posed by H1N1 are worthy of alarm. However, either in comparison to current contextual dangers, for example the dangers of smoking, or in comparison to an historical timeline of diseases, our fears of the H1N1 virus are undoubtedly overestimated.