Pär SegerdahlIt is a well-known psychological fact that people have great difficulties to understand probabilistic risks. What does it actually mean that the risk of developing breast cancer the next ten years is fifteen percent? In addition to the difficulties of understanding probabilities, mathematical expressions can cause a false appearance of exactitude and objectivity. It is often about uncertain evaluations, but expressed in seemingly definitive figures.

At our Monday seminar, Ulrik Kihlbom discussed another difficulty with understanding risk information. It can be difficult to understand not only the probabilities, but also what it is you risk experiencing. Sometimes, people face enormously complex choices, where the risks are high, but also the benefits. Perhaps you suffer from a serious disease from which you will die. However, there is a treatment, and it may work. It is just that the treatment has such severe side effects that you may die even from the treatment.

Ulrik Kihlbom interviewed physicians treating patients with leukemia. The doctors stated that patients often do not understand the risks of the treatment they are offered. The difficulty is not so much about understanding the risk of dying from the treatment. The patients understand that risk. However, the doctors said, no one who has not actually seen the side effects understand that the treatment can make you so incredibly ill.

Yet, it seems like quite comprehensible side effects: fatigue, serious infections, nausea and vomiting, stomach cramp, diarrhea, skin irritation, pain, and weight loss. Why would patients find it difficult to understand these risks?

Could it be that doctors have too high demands on “real” understanding? Must the patient, in order to “truly” understand the side effects, already have experienced the treatment? According to the doctors, experienced patients are at least easier to inform about the side effects. At the same time, the requirement that one must have had the experiences to really understand them seems too strong.

Rather, says Ulrik Kihlbom, doctors probably notice from the patients’ attitude that some of them underestimate what it is like to experience the side effects. Such attitudes can be sensed. The patients understand verbally that they are at risk of these side effects, but emotionally they do not really understand what the side effects are like, especially when they come together for a long time.

This resembles a general human difficulty. We often neglect how we ourselves are affected by our experiences. We project our present, unaffected self, and think: “I’m strong, I can handle those side effects.” However, when we actually experience the side effects, we are no longer strong! The self is not a constant, but changes with our experiences.

Here, then, it is not the probabilities that cause the difficulties, but the words. We understand the side effects verbally and can easily reproduce them. However, even words can cause a false appearance of objectivity: as if the experiences the words denote would not really reach us at our core. We separate ourselves from what we verbally understand we may experience, as if we could live our lives without being affected… without actually living them.

Ulrik Kihlbom has found a striking example of yet another aspect of the difficulty of understanding risk information. Not only probabilities but also common words such as “nausea” can create characteristic misunderstandings of risk information.

Pär Segerdahl

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