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Heuristics and biases leading to the health disinformation epidemic in America.

A behavioral science explanation for why millions fall for health dis-or-misinformation.
ImageNewristics Image04 February 2021

Misinformation, especially in healthcare, has turned into a problem that routinely troubles at least 3 groups of stakeholders - doctors, patients, and medical marketers. Doctors have to deal with self-medicating patients or those resistant to trying out evidence-based medicine. Patients either self-medicate or wait long enough to complicate an issue. Marketers and salespeople have to cut through others' disbelief in the information they share. There are fundamental biases that lurk underneath these behaviors.

To understand the resistance in accepting evidence-based medical information, we can assess perception at 3 levels:

  1. Sense-making
  2. The Availability Heuristic
  3. The Illusory Truth Effect

Making sense of an experience


When people hear stories of a medical intervention failing, they tend to blame someone or something. This often happens in the context of searching for plausible explanations. The act of finding a plausible explanation for something that has already occurred is called Sense-making. When people engage in sense-making, they look for justifications they can believe.

This brings us to the Availability Heuristic - Our brains prefer to engage with information that is readily available in our awareness for decision-making, evaluations, and judgments. That available information could be relatable stories of a medical process failing, the narrative of an anti-pharma YouTuber, or even a sensational news article that speaks of medical malpractices and poor ethics. If the brain is biased towards believing this, it readily integrates that information into the sense-making process.

The Illusory Truth Effect also plays a vital role in sense-making. It describes how familiar information seems more authentic than unfamiliar information. Familiar information is easier to process and digest (i.e., cognitive fluency). Fluency increases perceived accuracy & believability. When a story or opinion is both readily available resulting in awareness and familiarity through repeated exposure, we tend to judge it as true or mostly true. If the information is misinformation that sounds real enough, we rarely question its veracity.

This process of sense-making, coupled with the availability bias and the illusory truth effect is a pain point for all medical stakeholders.

How misinformation survives to reach our awareness

There is another layer of problems when it comes to medical misinformation. One could ask – Why does misinformation become a core part of our sense-making process? To understand that, we can look at 2 more biases - Negativity Bias and Survivorship Bias in the internalization of formal & informal news.


Negativity bias describes our tendency to remember negative events better and become more influenced by negative information rather than by positive or neutral events/information. This bias promotes negative memories that reach our awareness. So, it becomes easier to remember stories about harmful side effects or medical failures and any misinformation underlying the dangers of modern medicine.

Survivorship bias further increases the potency of negativity bias involved in sense-making. The survivorship bias is a logical consequence of information surviving or passing specific criteria. We only notice something if it survives a process. For example, if a news agency prefers to share medical failures, we would rarely hope to hear stories of medical successes. As a result, there is a disproportionate number of negative stories in the news.

In our awareness, the positive stories never passed the selection criteria - the agency only selects negative stories to share. If news agencies selected only positive stories, the negative stories would fail the selection criteria and never reach public awareness. When the survivorship bias occurs for misinformation or negative information, it becomes a false representative sample of what's happening globally.


Misinformation is highlighted through survivorship bias and negativity bias. Our availability heuristic selects that misinformation and attributes a high degree of accuracy to it because of the illusory truth effect. A combination of these is integrated into the sense-making process because people want to find a plausible explanation for their negative experiences.

How can one counter this misinformation loop holistically?

Step 1: Build awareness of the biases at play.
Step 2: Healthcare professionals and marketers design their messaging to address sense-making needs in addition to health information.