Source: Alcatraz - Inside the Main Cellhouse (4409974876)" by Daniel Ramirez via Wikimedia Commons

Going back to the 1950s, social and cognitive psychologists noticed that people’s beliefs tend to become more coherent over time. For example, a couple buying a house might initially notice both the positive and negative elements of that house. If they decide they are not going to buy that house, they may start to focus on the negatives of that house and to discount the positives. Similarly, if they decide this house is one they are quite interested in buying, they may now focus mostly on the positives rather than the negatives.

You can think of this dynamic as a spreading coherence. Initially, you don’t have a strong attitude toward something, but eventually you come to like or dislike a particular item. As your attitude changes strength, you increase the weight you give to information consistent to that attitude and decrease the weight you give to information that is inconsistent with it. After a while, your set of beliefs is fairly coherent.

Most of the work that has been done demonstrating this kind of spreading coherence has been focused on beliefs and attitudes. That is, it is focused on information. A paper by Dan Simon, Douglas Stenstrom, and Stephen Read in the September, 2015 issue of the Journal of Personality and Social Psychology explored whether people’s feelings and emotions are also part of this spreading coherence.

In their studies, they first had people do a pre-test to evaluate how strongly a particular fact might lead someone to a particular conclusion. For example, they would evaluate whether someone could make a drive that normally takes 45 minutes in 40 minutes. This pre-test was done as part of what participants thought was a separate study.

Then, participants were introduced to a legal case and were told that they were going to be playing the role of a mock juror. For example, one study involved a defendant accused of murdering a security guard and stealing money from his employer. There were lots of facts that were part of the case. For example, as part of the alibi, the defendant was seen at a location that is normally a 45 minute drive from the scene 40 minutes before the crime was committed.

The key manipulation in one study was that some participants were told that an eyewitness was absolutely certain that the defendant was the perpetrator, while other participants were told that the eyewitness was not certain at all. This manipulation led one group of people to have much stronger initial negative feelings about the perpetrator than the other.

As you might expect, people given the confident eyewitness were much more likely to conclude that the perpetrator was guilty than people who were given the unconfident eyewitness. In addition, there was a coherence effect for the facts in the case. People who voted guilty agreed mostly with facts that supported . People who voted not guilty agreed with facts that supported the perpetrator's alibi. To use the example, people in the pretest might have thought it was somewhat likely that a person could make a drive that normally took 45 minutes in only 40 minutes. In the post-test, though, if people thought the perpetrator was guilty, then they now thought it was quite likely that he could make a 45 minute drive in 40 minutes. If people thought the perpetrator was innocent, they thought it was highly unlikely that he would be able to make the 45 minute drive in 40 minutes.

A second study using a similar design manipulated people’s sympathy for the perpetrator. In this case, the person being evaluated was a woman accused of a university exam. Prior to reading the case, some participants were led to feel sympathetic to the woman by telling them that a few months before the incident she lost her younger brother after he was hit by a drunk driver. This piece of information is not really relevant to the facts of the case, but it is designed to influence people’s feelings toward the accused.

As you might expect, people who were led to be sympathetic to the accused were much less likely to find her guilty than those who were not led to be sympathetic toward her. People who found her guilty agreed more with facts that supported her guilt than facts that supported her innocence. People who found her innocent agreed more with facts that supported her innocence than facts that supported her guilt.

These studies suggest that the coherence we see in beliefs extends to feelings as well. People’s feelings can help drive conclusions that ultimately affect their beliefs as well. Thus, even though we tend to treat facts and emotions separately, the strength of our beliefs can influence the strength of our feelings and similarly the feelings we have can affect what we believe.

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