What’s the difference between risk assessment and risk perception?
How extraordinary! The richest, longest-lived, best-protected, most resourceful civilization, with the highest degree of insight into its own technology, is on its way to becoming one of the most frightened.
As political scientist Aaron Wildavsky notes, Americans are frightened of health risks. There’s just one problem: they’re frightened about the wrong things.
Everyone from anti-vaxxers to lactivists needs to understand that their perceptions of risk are totally out of line with actual risk.
Anit-vaccine advocates are frightened about vaccines although vaccines are safe and effective, one of the greatest public health triumphs of all time. And they’re not frightened of the deadly diseases that vaccines prevent because they are profoundly ignorant of what they haven’t personally seen.
Food fetishists are frightened of gluten, additives and spurious “toxins,” and happily dose themselves with nonsensical and often dangerous supplements and “detoxes.”
Natural childbirth advocates fear technology in birth although obstetric technology has led to a 90% drop in neonatal mortality and a nearly 99% drop in maternal mortality in the past 100 years. And they’re not frightened of the myriad causes of perinatal and maternal death because they are profoundly ignorant of what they haven’t personally seen.
Lactivists are frightened about the purported “harms” of formula feeding which are essentially non-existent and they’re not frightened of the risks of infant dehydration, starvation and death because they live in a fantasy world where everything natural is good and everything technological is bad.
In every case, the risks they perceive as large are actually minuscule, and the risks they perceive as minuscule are actually large. In other words, their perception of risk has nothing to do with the actual risk assessment.
Risk assessment is the mathematical determination of a specific risk, and is usually carried out by professionals in statistics or related disciplines. Risk perception is the belief about a specific risk and is typically the province of lay people. Why is there often such a wide gulf?
Risk perception is modified by factors that have nothing to do with actual risk. According to David Kane in Science and Risk: How Safe is Safe Enough, these factors include “newness” of the risk, control, and benefits.
What is the “newness of the risk”?
Generally, a risk that has always existed is regarded as an acceptable risk, while newer risks that are brought to the public eye receive greater scrutiny. This intense examination makes the new risk appear to be more dangerous.
That is especially true when the magnitude of the risk is unknown to many (the risk of death during childbirth) or has not been directly witnessed (the risk of death from vaccine preventable diseases). It is also affected by the naturalistic fallacy, the claim that the way that things were is the way that they ought to be.
The second factor is control.
An individual is more willing to accept the risk of an activity of which he or she is in direct control… This underlying factor explains why … indirectly controlled activities have a high perceived risk.
A key type of control is the decision to be exposed to a risk. Voluntary risks involve this kind of choice, while involuntary risks lack this element of control. Because voluntary risks involve a choice based on an individual’s own set of values, [research has shown that] the acceptance levels are a thousand times greater than those of involuntary risks.
For example, even when homebirth advocates are apprised of the increased risk of neonatal death, many will still choose homebirth. It seems to them that the risk they choose (to have a homebirth) must be smaller than risk of hospital birth.
The third factor is benefits.
The public is only willing to tolerate a minute level of risk for activities which it considers to be of little value, such as constructing nuclear power plants. Conversely, for those events which the public perceives great benefit, the acceptance level is quite high.
Kane includes a graph that dramatically illustrates this phenomenon. Here’s a modified version of the graph.
As the graph demonstrates, large risks are considered acceptable if the benefits are valued highly.
For these reasons, anti-vaxxers’ perceived risk of vaccination is much higher than the actual risk. They often perceive the risks of “new” vaccinations are far higher than “old diseases.” They are more frightened of risks posed by mandated vaccination than the far higher dangers of voluntarily rejecting vaccines. And since they don’t understand the magnitude of the benefit, they erroneous conclude that risk of vaccination is not acceptable.
Similarly, for homebirth advocates the risk of hospital technology are perceived as far higher than the risk of birth in the traditional venue of the home. They are far more frightened by the risks of undesired hospital policies than the far higher dangers of freely chosen homebirth. And for those who understand that the risk of neonatal death is higher at homebirth, it is judged acceptable because the perceived benefits are valued so highly.
The wide gulf between risk assessment and risk perception has led to a marketing bonanza whereby a variety of industries and personalities market products as diverse as elimination diets, breastfeeding and detoxes by capitalizing on the fact that most people have very little actual medical knowledge and a childlike belief in the naturalistic fallacy — that if it’s natural it must be good.
Anti-vaxxers, food fetishists, homebirth advocates and lactivists (among others) need to understand that their perceptions of risk are totally out of line with actual risk. Until they do, they will continue to erroneously believe that dangerous choices are safe, and safe choices are dangerous.