A rumor is a report without known source that spreads from person to person. It could be true or false; it might just be the common gossip heard in a restaurant or a passing comment on the street. Regardless of whether the rumor is real or not, it may inspire fear, anger or anxiety. Rumors can also be used to influence an event or decision, such as the rumor about the bombing of a school that resulted in many students staying home from class.
People create and spread rumors in order to fulfill various needs. One of the most basic functions is to warn people about a potential future negative event (for example, “The tsunami is coming! Get out of town!”). Another function is to help people manage a current threat, such as a natural disaster or an attack against a specific group (for example, “I heard that the Israeli government is behind this tragedy!”).
Rumors can also serve as an emotional vent, allowing individuals to express frustration with the policies of others. For example, rumors of corruption or special privilege in the food rationing programs necessary for World War II were more likely to be believed by people who disagreed with the Roosevelt administration than by those who agreed. Rumors can also serve to build up self-esteem and a sense of power by derogating members of other social groups. For instance, the rumor that McDonald’s was hiring only white employees helped some African-Americans feel a greater sense of power and worth over those who did not.
Researchers have studied the nature of rumors for decades and have identified several factors that influence how they spread. The most influential are:
1. Veracity of the rumor. A rumor is more likely to be believed if it comes from a credible source. This is especially important when the rumor is concerning a serious matter, such as an impending disaster or terrorist attacks.
2. The number of people involved in spreading the rumor. The more people involved, the more likely it is that the rumor will be spread. This is because each individual can contribute to the overall confidence level in the rumor by sharing it with his or her network of acquaintances.
3. The speed at which the rumor is spreading. The faster the rumor is spreading, the more credible it becomes. This is because more people will be able to validate the information in a short period of time.
The COVID-19 pandemic illustrates how a rumor can quickly spread in a tightly connected community. This is demonstrated in the timeline below, which shows how the support ratio for each rumor changes over time, with some rumours remaining unverified throughout the event, while others are labelled as true or false. The z-score values on the graph represent the percentage of retweets that each rumour receives above or below the average of all rumours.