The false consensus effect is a cognitive bias where individuals tend to overestimate the extent to which their own thoughts, actions, and opinions are shared by others. Essentially, people believe their personal views are much more common in the population than they actually are. This effect is considered a facet of egocentric bias, meaning it stems from a self-centered perspective where one assumes others are similar to themselves. When asked to estimate population statistics,
individuals often rely solely on their own experiences and project them onto the broader group, leading to an overestimation of shared opinions. Consequently, those who hold differing views are often perceived as being part of a minority, while the majority is assumed to agree with one's own stance.
Classic Demonstrations of False Consensus
A well-known example illustrating the false consensus effect comes from a 1977 study by Ross, Greene, and House. In this experiment, students were asked to participate in an unusual task: walking around a campus wearing a sandwich board that bore the word "repent." The results clearly demonstrated the bias. Among the students who agreed to wear the sandwich board (approximately 50% of participants), they estimated that most of their peers would also agree to do so, with an average estimation of 63.5%. Conversely, those students who refused to participate in the experiment reported that they believed most of their peers would also refuse.
This study highlights how individuals project their own behavioral choices onto others, assuming a consensus that aligns with their personal decision. People exhibiting the false consensus effect go beyond simply not considering other perspectives; they actively believe their viewpoints are widely accepted by the majority. While some psychologists use the terms "false consensus" and "egocentric attribution bias" interchangeably, as Ross, Greene, and House did in their paper, the core phenomenon remains the same: a biased perception of shared beliefs.
Further Insights from Ross, Greene, and House
The second part of the 1977 study by Ross, Greene, and House further solidified their findings. Participants were given a questionnaire presenting specified situations and asked to choose one of two options. They were then asked to estimate the percentage of the population that would choose each option. Across all four scenarios presented, subjects consistently rated the option they personally chose as the most probable choice for the general population. This consistent pattern reinforced the false consensus hypothesis.
Ross, Greene, and House concluded that their results supported the idea that "intuitive estimates of deviance and normalcy, and the host of social inferences and interpersonal responses that accompany such estimates, are systematically and egocentrically biased in accord with his own behavioral choices." This means that our judgments about what is normal or deviant, and the social conclusions we draw from these judgments, are heavily influenced by our own actions and beliefs, leading to a skewed perception of consensus.
False Consensus and Rationality
The question of whether the false consensus effect is a rational thought process has been explored through the lens of Bayesian inference, a statistical method for making probability predictions. Psychologists often use Bayesian reasoning to determine the rationality of subjects exhibiting the false consensus effect. In Bayesian updating, individuals use prior probabilities to make estimates and then adjust these probabilities as they acquire more information.
However, studies suggest that the false consensus effect is not entirely rational. For example, in experiments like one by Kreuger and Clement involving an urn with chips, participants often overestimate probabilities and tend not to pay sufficient attention to sample size when making predictions. Despite the statistical law of large numbers indicating that larger samples have less variability, people often claim that large and small samples have similar variability. Such evidence suggests that egocentric viewpoints tend to be predominant, leading to biases that deviate from purely rational statistical reasoning and contributing to the false consensus effect.
