Even Known Irrelevant Information Can Bias Decision Making

If you follow me on Facebook then you know over the weekend Jane and I had a little scare that landed her in the emergency room for about three hours Saturday afternoon. Our time there included a CAT scan of her brain.

Jane had been working out Friday morning with a friend when she felt a sudden explosion (her word) in the back of her head, right in the middle. She said the pain was a 10 on a scale of 10 in the moment but quickly subsided. It did leave her with a mild headache but nothing else so she didn’t think about it anymore until the same thing happened that night.

I wasn’t aware of either episode until she told me about them late Saturday morning. We decided she should call a couple of doctor friends to get their take on the situation just to be safe. Maria, an urgent care doctor, and Mike, an ER doctor, both agreed Jane should go to the emergency room as a precaution.

About a year and a half ago one of Jane’s brothers had brain surgery for bleeding on his brain caused by a subdural hematoma. He had fallen and that caused bleeding inside his scull, which put pressure on his brain. Scary stuff. When describing the incident to our ER friend Mike, Jane mistakenly said her brother had an aneurism. Mike called a local emergency room so we would get in quickly. He also alerted the doctor on call about Jane’s situation.

As we interacted with the doctor in the emergency room he suggested a brain CAT scan based on what Jane described AND because of the information that her brother had an aneurism. Aneurisms can be heritable and therefore caution is needed with family members. The only problem was Jane’s brother didn’t have an aneurism. We confirmed that fact through a series of quick texts. However, once the ER doctor heard the word aneurism it changed his thinking and diagnosis.

Here’s the interesting part about the doctor’s decision making. The doctor told us if he’d not heard the word aneurism, based solely on Jane’s responses to his questions he would have just assumed she strained something while working out and would have sent her home. But his thinking had become biased by irrelevant information. I found it fascinating that this highly trained, logically thinking doctor recognized the bias in his decision making because he even said so! But he couldn’t change his thinking and recommended the CAT scan. I even confirmed, asking him, “If an aneurism had not been mentioned we would not be talking about a CAT scan, right?” He agreed. Despite discussing the irrelevant information at length we decided to go ahead with the CAT scan as a precaution. It came back normal and that gave Jane great relief.

For the most part people are emotional creatures and sometimes rationality just doesn’t cut it. We see it all the time. For example, once people hear about a shark attack they stay out of the water even though such attacks are incredibly rare and they stand a much greater chance of dying in a car accident. It does little good to rationalize with a veteran who suffers from PTSD when he hears a loud sound because his reality has been changed by prior experiences.

For Jane and the doctor the possibility of “what if” led them to a wholly different decision than they would have made otherwise. Certainty is better than uncertainty, no matter how small the odds. In the end, all three of us were more relieved than we would have been despite knowing what we knew about the irrelevant information.

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