Primacy Bias

Posted in Principles

Give these two descriptions, which version of Steve do you prefer: “Steve is smart, diligent, critical, impulsive, and jealous” or “Steve is jealous, impulsive, critical, diligent, and smart?” Even though both descriptions contain the same adjectives, the majority of participants in a study felt more positively about the first description, where Steve’s positive attributes are listed first. This bias towards the information that is presented first is called the primacy bias, and it can have serious and unintended effects.

For example, listing a political candidate’s name first on the ballot – especially for low-visibility, “bottom of the ballot,” non-partisan candidates – has been shown to increase their percentage of the vote by up to 5% in some cases. In other words, in elections where we cannot anchor to a political party or where we might not know the candidates well, we sometimes default to whomever is listed first. Even our memories fall prey to the primacy bias; for example, when patients were asked to recall information from a doctor’s visit, they remembered just over 50% of what was told to them, but that information usually included what was told to them first.

Although the primacy bias is difficult to combat in all its forms, small steps like randomizing the order in which candidates’ names appear on the ballot can help us overcome it. We can also harness primacy to own advantage – for example, listing the item that is most critical for us to remember first on a to-do list. Doctors can make sure that they discuss the most important health information first.

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