samedi 30 juin 2018

134- Risk perception


An interesting article published in May on the Spanish blog "El ecologista transgénico" (The transgenic ecologist) informs us about the perception of risk by the public, and warns us against the enormous media pressure that we suffer daily, with the sometimes mistaken perception of certain topics.

I'm very interested in this article because agriculture, and in particular pesticides, are among the targets most frequently affected by this problem, very often in an unjustified way.

"Perception of risk: a dangerous topic
May 12, 2018

Mistakes in the perception of risk are the basis of many problems in the communication of science, so I will dedicate this article to this topic, trying to clarify concepts through several examples. Because every day, in our daily life, we must take an infinity of decisions which are an exercise of balance between benefits and risks, some unconscious, others more reasoned. Unfortunately humans are not very good at assessing these risks. It greatly complicates our ability to make consistent decisions, from medical decisions, more or less important, to the choice of food we bring to our mouths.

In fact the evidence is clear, we can't avoid these mistakes. Our apparent irrationality on these points is the result of innate processes that operate outside of our conscious control. There have been identified a number of emotional "fear factors" that make some potential threats more fearful than others, unrelated to the obvious:
-       Risks created by man scare us more than natural risks. It is therefore likely that we are more frightened by transgenic crops, radiation from nuclear power plants or chemical plants, than by "natural" risks such as unpasteurized milk, natural medicines or carcinogenic radiation from the sun.
-       We are more concerned about risks we can't control and we tend to underestimate risks we can control. For example we overestimate the risk of glyphosate (or other phytosanitary products) but we underestimate the risk of not eating enough fruits or vegetables, or sedentary lifestyle.
-       Imposed risks make us more afraid than those we voluntarily take. For this reason, the perception of risk is greater in the case of radiation from nuclear power plants than in the case of sun radiation, to which we voluntarily expose ourselves.
-       We are bad at assessing long-term risks and benefits. We have an innate tendency to focus on the short term. For example, when diseases such as measles or mumps disappear, the benefits of vaccination that helped overcome them are no longer evident and can be questioned.
-       We often forget to consider the risk of doing nothing, or the alternative.

These mental shortcuts and our desire for simple answers about causality, risk, and benefit, lead to some common mistakes in the way we act in our own lives.
Danger and risk

Danger and risk are two different but related concepts.

A danger is an agent that has the potential to cause harm.
Risk measures the probability of harm by a danger.

Dangers become risks only if there is an exposition to it. Example: solar radiation is a danger. But if I never expose myself (or protect myself) to radiation, I will not face the risk of burns or melanomas, although the danger exists. Despite this difference, we tend to consider all dangers as risks, regardless of our level of exposure.

This phenomenon is very evident in the classification of IARC carcinogens (IARC  Danger identification is the first step of the risk assessment, but it is not, in itself, a risk assessment, yet we constantly see hazard identification studies presented as evidence of real risks. These classifications are based on the strength of evidence and not on the degree of risk. Two risk factors could be included in the same category, although one increases the risk of cancer threefold and the other only increases it by a small fraction. A good example could be tobacco and processed meat, both included in category 1. According to Cancer Research UK ( -need-to-know /), smoking causes 19% of all cancers. On the contrary, it is estimated that "only" 3% of all cancers are caused by processed meat and red meats combined. As a result, evidence that processed meat causes cancer is as strong as that of tobacco, but the risk of tobacco is much higher.

All dangers are not equal

As we have seen, not all dangers are equal, they can affect a distinct number of people and be more or less damaging. By observing the graph, we divide hazards into four categories based on the number of people affected and the severity of the damage. The nature of the product (natural or synthetic) has nothing to do with its dangerousness.

However, we sometimes tend to consider that all dangers we pay attention to are as damaging as each other. The development of the anti-vaccination movement shows this tendency to see all risks as equal (considering the dangers of vaccination and the dangers of diseases as equivalents in both gravity and risk of problem). The diseases that are prevented by vaccination belong to the upper right-hand panel of the graph. Vaccinations move the danger of these diseases to the left upper cadre by significantly reducing the number of people affected by these diseases. On the other hand, the vaccines themselves possess a generally low danger on a limited segment of the population, which places them in the lower left-hand frame. Yet, in many people's minds, the extremely rare risks (real or imagined) associated with vaccines have become equal to or greater than the (real) risks of catching the disease. The problem is the same for food additives.


We are permanently exposed to a large number of dangers, some of which may pose a risk to our health if we expose ourselves to them, if they are in excessive concentration or if they are too frequent. Errors in the perception of risk are the basis of many problems in the social communication of science. These errors are partly due to our poor ability to correctly assess these risks (they can also be intentional). To avoid them, we must evaluate each hazard separately, analyzing its damage potential and level of exposure, as well as possible alternatives or the consequences of avoiding it, to find out if something really represents a risk.

More information on this topic:

The confusion created around the difference between danger and risk is carefully maintained, with a desired objective, usually hidden, intended to favor sales or to provoke a change of opinion or behavior.
This is undoubtedly what has been happening for several years against conventional agriculture, to promote the consumption of organic products. Those who communicate in this way are capitalist companies that distribute organic food, or environmental NGOs that try to attract new members, or to increase their power.
This market is very lucrative, and the means used to develop it don't hesitate to denigrate everything that stands in its way.
Attracting the consumer by playing on his fears is the only thing that matters.
And the collateral damage caused, which is sometimes serious, does not matter.


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