As a general rule outcomes that are more vivid more tangible and have better defined consequences exert greater influence on our decisions. We can see this in medical decision-making by comparing disorders that differ in how vivid they are, how tangible they are .

People are less willing to sacrifice money

Let’s take two disorders: chronic diabetes and chronic depression, both are frankly debilitating and both can greatly reduce one’s quality of life. When surveyed people report the depression leads to greater reductions in quality of life compared to diabetes.
Mental illnesses are seen as particularly burdensome, they affect one’s quality of life more than physical illnesses.

But the same people were asked how much they be willing to pay to avoid each condition and they were willing to pay more money to avoid diabetes than they were to avoid depression.

People recognize that mental health is more burdensome, but it’s less tangible than something like diabetes and so people are less willing to sacrifice large amounts of money to avoid it. Of course this question was hypothetical you can’t just make diabetes or depression disappear with the monthly copayment, but the general principle can be seen in our society’s priorities.

Historically there’s been much more spent on research and treatment of physical illness compared to mental illness even though people do understand just how debilitating mental disorders can be. This doesn’t just hold for money. Similar discrepancies can be seen when you ask people how much of their lifespan they be willing to give up to avoid different diseases. Their answers don’t necessarily match on to their sense of disease burden.

Vividness influences our medical decisions

Vividness influences our medical decisions in other ways too.  Suppose you were an older adult in a high risk demographic group for prostate cancer. A series of tests indicate a likely prostate tumor with unknown prognosis. You have the choice of taking action, perhaps by a combination of radiation therapy and surgery or taking no action now and instead monitoring the possible progression of the tumor.

Again this is a hypothetical example but I’ve chosen prostate cancer because it often involves a slow-growing tumor that doesn’t necessarily require treatment. What do you do? Take action or wait? When faced with decisions of this general flavor is often a bias toward action. We want to take action for known and vivid risks because we don’t want the regret of failing to act.

Now switch to a different hypothetical scenario: You are in a high risk group for safe Parkinson’s disease. It’s estimated that you’ll have about a 5% chance of suffering from that disease over the next decade. There is an experimental drug that is been shown to reduce the risk in people in your high-risk group about 2%, but it also has a small chance say 1% of damaging the dopamine neurons in your brain directly leading the symptoms that are similar to Parkinson’s disease anyway.

Now as I described the scenario the choice seems clear you have a 5% chance of contracting the disease without the drug and only a 3% total chance of having the disease or similar symptoms with the drug. So you should take the drug. But when faced with scenarios of this sort people often avoid taking action. Why? It’s because they fear the regret associated with making a choice that leads to harm. This is sometimes called the omission bias.

Harms of omission are our fault

This bias works against us we face rare or unknown risks. Many children have become sick or died because they didn’t receive a freely available vaccine. When parents are surveyed the primary factors that predict that their children won’t be vaccinated are the perceptions that vaccines are dangerous and ineffective, along with the omission bias.

Parents who don’t vaccinated children are more fearful of taking an action that they perceive could harm their child compared to parents who do vaccinate. Our decision biases matter. Many public health problems arise because of behaviors whose potential negative consequences are long-term and uncertain.

Just because you have dessert this evening or every evening for that matter doesn’t guarantee they are doomed to cardiovascular disease, diabetes and an early death and. The behavioral economist George Lowenstein points out that in many medical decisions the option that’s best for us and best for society involves tangible costs but intangible benefits.

It’s no wonder that people are willing to pay a cost say by exercising regularly or giving up fatty foods in order to receive some uncertain distant benefit. I’ll move now to the third and final factor that shapes our medical decisions: other’s opinions. We often consider what other people think when making our own medical decisions for at least two reasons: one is that our medical decisions have consequences for others.