The term, “confirmation bias” has long been used by scientists and social scientists to explain a particular flaw in scientific experiments which causes experimenters to emphasize evidence that supports their theory. Underlying it is a human need to be right.
Now a new study elaborates on the confirmation bias, but comes up with a different term to describe it—“desirability bias.” The study focused on the recent Presidential election between Donald Trump and Hillary Clinton.
The study by Ben M. Tappin, Leslie van der Leer and Ryan T. McKay, which was published in the Journal of Experimental Psychology, espouses the theory that a desirability bias leads people to prefer new desirable evidence over new undesirable evidence when updating their beliefs about something. While the authors speak of desirability bias in general, their study is based on their subjects’ attitudes towards the recent US Presidential election.
The researchers began by asking subjects which candidate they preferred. Researchers then set a marker on a table between the candidate’s names and asked participants to place the name of the candidate on the marker they thought would win. The person running the experiment then informed the subjects of the results of the most recent poll (which was made up). The marker was again placed in the center of the table and the candidate names on each side. The subjects were then asked to place a name on the marker based on the new poll (evidence) they had received, indicating a certain candidate was ahead in the polls.
The results of the experiment proved the existence of a desirability bias. When the new poll backed up a subject’s prior belief about which candidate would win, the subject again placed his desired candidate’s name on the marker. However, when the new poll did not back up a subject’s prior belief about which candidate would win, the subject nevertheless resorted to putting his desired candidate’s name on the marker. Thus the new evidence had no effect on a subject’s decision.
Whether you call it a confirmation bias or a desirability bias, this research can be used to explain not only Presidential preferences, but also how bias affects almost every judgment we make, especially if we have a narcissistic feature in our personalities.
First and foremost, the theory can be applied to scientific research. Whenever a new experiment is done purporting to prove a certain theory, the first thing we must ask is if there is a confounding variable. The most prevalent confounding variable is experimenter bias. Experimenters set out to prove a theory, and their confirmation bias (or desirability bias) causes them to emphasize results that prove their theory to be correct and de-emphasize results that invalidate their theory.
In a larger sense the desirability bias can be applied to all aspects of our beliefs. When people make judgments about situations or things that come up during their daily lives without—or despite—knowing all the facts, this is an aspect of the desirability bias. Some religious people will not eat certain foods on certain days, based not on facts about nutrition, but on their religious bias. You can’t argue with them about these practices. They are certain they are right and others are wrong.
Some black people, along with some white liberals, rush to judgment every time a white cop kills a black man. They immediately see the incident as a manifestation of white discrimination against blacks. Even if evidence later exonerates the white cop in a court of law, these blacks and liberals hold on to their prior beliefs about the situation. They sometimes even go so far as to stage protests and even conduct riots in order to sway public opinion on the subject. They are so caught up in their belief system that no facts of any kind can dissuade them of their strong feeling of injustice. And the more of them there are who believe the same thing, the more convinced they are that they’re right.
The main reason couples fight and never seem to be able to resolve their issues is in their need to be right. The desirability bias in this case causes them to see their own point of view but not their partner’s point of view. The old saying that there are always two sides to every story totally escapes them. When I tried using that saying with a couple I was recently treating, one of the members of the couple immediately turned to me and said, “Usually I believe in that saying, but not in this case. In this case I really am right and she’s really wrong.”
The desirability bias has an effect on families. A husband may sexually abuse his young daughter, but when the daughter tells her mother about the incident, the mother becomes upset and replies, “Don’t ever talk about your father that way.” She is biased toward protecting her husband. It may affect financial decisions. You may become convinced that a certain stock is going to rise in value not based on the evidence, but based on a strong feeling you have that it is going to rise. So you buy a huge amount of the stock, thinking that you are right and everybody else doesn’t get it. And then the stock goes down and you lose your money.
The desirability bias also affects what we believe about ourselves. We may want to believe that we are well liked, so we only notice those things that back of this belief, but ignore the many signs that in fact we are not well-liked. We want to think our family is a happy family, so we only take note of evidence that supports that notion while ignoring the negative evidence—i.e., our kids are taking drugs, missing their classes, drinking while driving.
“Our heart trumps our head,” say the authors of the study on the desirability bias. What that means is, despite evidence to the contrary, we believe what we want to believe. A hundred validated and reliable experiments could be done disproving our beliefs, but we will still hold to them.
Eventually, this will cause humanity as a whole to be in peril. Many people still do not believe in global warming despite evidence gathered over many years proving that it does. People who are plowing down our rain forests do not believe that they are necessary for our survival. People who pollute our oceans do not believe they are doing anything wrong. “I’m just throwing a few plastic bags in a huge body of water,” they may rationalize. “What harm can that do?” People who develop H-bombs do not properly consider the ramifications of what they’re doing. They desire to do it and so they do it.
Tapin, et al. have done an important study. But will anybody pay attention to it? Only those who want to believe what the experiment says.