In social psychology, pluralistic ignorance (also known as a collective illusion) is a phenomenon in which people mistakenly believe that others predominantly hold an opinion different from their own. In this phenomenon, most people in a group may go along with a view they do not hold because they think, incorrectly, that most other people in the group hold it. Pluralistic ignorance encompasses situations in which a minority position on a given topic is wrongly perceived to be the majority position, or the majority position is wrongly perceived to be a minority position.
Pluralistic ignorance can arise in different ways. An individual may misjudge overall perceptions of a topic due to fear, embarrassment, social desirability, or social inhibition. Individuals may develop collective illusions when they feel they will receive backlash when they think their belief differs from society's belief. From a group-level perspective, and arguably the most accurate way of analyzing pluralistic ignorance, causes of divergence between public behaviors and private opinions are caused by conservative lags (change in attitude without a change in behavior), liberal leaps (change in behavior without a change in attitude), and social identities (conforming to societal expectations of how one should behave based on the traditional ideals of the group).
However, pluralistic ignorance describes the coincidence of a belief with inaccurate perceptions, but not the process by which those inaccurate perceptions are arrived at. Related phenomena, such as the spiral of silence and false consensus effect, demonstrate that pluralistic ignorance is not unique in its inaccurate assumption of others' opinions and these misconceptions can lead to negative consequences like groupthink and the bystander effect.
Floyd Allport first discussed the phenomenon of "literal attitude behavior inconsistency" in 1924, observing society's tendency to conform to social norms at a large scale even in the absence of personal agreement to those social norms. In an effort to explain this inconsistency, Allport presented the idea that individuals don't often act on personal conviction unless they believe those convictions are shared by the individuals around them. In Allport's 1931 book titled Students Attitudes: A Report of the Syracuse University Research Study, which he co-wrote with his student Daniel Katz, the term "pluralistic ignorance" was used for the first time.
Allport and his students Daniel Katz and Richard Schanck produced studies of attitude change, and racial stereotyping and prejudice, and their pursuit of the connections between individual psychology and social systems helped to found the field of organizational psychology.
Further behavioral, economic, and social psychology research was done by Todd Rose to demonstrate the interchangeability of the terms pluralistic ignorance and collective illusions. His findings of historical events, scientific studies and social media patterns indicate that by using either term you are saying the same thing. The societal systems like ours unconsciously participate in perpetuating false beliefs and narratives with a desire to fit in.
Although social psychologists, such as Allport and Katz, initiated the development of pluralistic ignorance, work pertaining to this phenomenon has since been heavily conducted by sociologists and public opinion researchers. This shift, in part, can be attributed to laboratory experiments, the primary research method of social psychology, proving insufficient in studying the inconsistencies between attitudes and norms.
As Allport was the first person to bring awareness to the phenomenon of pluralistic ignorance, it is important to point out that his analysis of this phenomenon was strictly at the individual level. He strongly disagreed with expanding the discussion to the larger group and involving the concept of shared cognition, "the collective cognitive activity from individual group members where the collective activity has an impact on the overall group goals and activities."
This is not a unanimous stance for all those who have studied pluralistic ignorance. Sargent and Newman acknowledge that the individual aspects of pluralistic ignorance are important to discuss, but are lacking in providing a full picture of all the moving parts at play in the study of pluralistic ignorance. In their perspective, pluralistic ignorance is defined as "a group-level phenomenon, wherein individuals belonging to a group mistakenly believe that others' cognitions (attitudes, beliefs, feelings) and/or behaviors differ systematically from their own, regardless of how the misperception arises".
Prentice and Miller conducted a contemporary study on pluralistic ignorance, examining individuals beliefs on alcohol use and estimating the attitudes of their peers. The authors found that, on average, individual levels of comfort with drinking practices on campus were much lower than the perceived average. In one subset of experiments they traced the attitude change toward alcohol consumption of men versus women over the semester. In men, the authors found a shifting of private attitudes toward this perceived norm, demonstrating a form of cognitive dissonance. Women were found to have no shift in attitude over the course of the semester. Additionally, students perceived deviance from the social norm on alcohol use was correlated with various measures of campus alienation. Even though that deviance from the social norm was only perceived, it shows how isolation from the larger population can lead to larger differences between an individual's belief and the populations belief, leading to pluralistic ignorance. This study showed that the university students showcased pluralistic ignorance by individuals believing that the general populations comfort level with drinking practices was significantly higher than their personal comfort level, when in reality the individuals comfort level was quite similar to the general populations comfort level.
Additional research has shown that pluralistic ignorance plagues not only those who indulge, but also those who abstain. Examples consist of individuals beliefs on traditional vices such as gambling, smoking and drinking to lifestyles such as vegetarianism. With the latter showcasing that pluralistic ignorance can be caused by the structure of the underlying social network, not exclusively cognitive dissonance, demonstrating how pluralistic ignorance can arise through a variety of methods.
Pluralistic ignorance was blamed for exacerbating support for racial segregation in the United States. It has also been named a reason for the illusory popular support that kept the Communist Party of the Soviet Union in power, as many opposed the regime but assumed that others were supporters of it. Thus, most people were afraid to voice their opposition.
Another case of pluralistic ignorance concerns drinking on campus in countries where alcohol use is prevalent at colleges and universities. Students drink at weekend parties and sometimes at evening study breaks. Many drink to excess, some on a routine basis. The high visibility of heavy drinking on campus, combined with reluctance by students to show any public signs of concern or disapproval, gives rise to pluralistic ignorance: Students believe that their peers are much more comfortable with this behavior than they themselves feel.
Hans Christian Andersen's fairy tale "The Emperor's New Clothes" is a famous fictional case of pluralistic ignorance. In this story two con artists come into the Emperor's kingdom and convince him that they make the finest clothes in all of the land that can only be seen by anyone who was not stupid. The con artists continued to steal gold, silk and other precious items for their "unique creation". Out of fear for being seen as stupid, all of the emperor's men and townspeople kept silent about the fact they could not see the emperor's clothes until finally a small child comes forth and says that the emperor isn't wearing any clothes. Once the child is willing to admit that he cannot see any clothes on the emperor, the emperor and townspeople finally admit that the emperor has been tricked and that there was never an outfit being made.
Pluralistic ignorance has also been blamed for large majorities of the public remaining silent on climate change—while 'solid majorities' of the American and UK public are concerned about climate change, most erroneously believe they are in the minority with their concern. It has been suggested that pollution-intensive industries have contributed to the public's underestimation of public support for climate solutions. For example, in the U.S., support for pollution pricing is high, yet public perception of public support is much lower.
In August 2022, Nature Communications published a survey with 6,119 representatively sampled Americans that found that 66 to 80% of Americans supported major climate change mitigation policies (i.e. 100% renewable energy by 2035, Green New Deal, carbon tax and dividend, renewable energy production siting on public land) and expressed climate concern, but that 80 to 90% of Americans underestimated the prevalence of support for such policies and such concern by their fellow Americans (with the sample estimating that only 37 to 43% on average supported such policies). Americans in every state and every assessed demographic (e.g. political ideology, racial group, urban/suburban/rural residence, educational attainment) underestimated support across all policies tested, and every state survey group and every demographic assessed underestimated support for the climate policies by at least 20%. The researchers attributed the misperception among the general public to pluralistic ignorance. Conservatives were found to underestimate support for the policies due to a false consensus effect, exposure to more conservative local norms, and consumption of conservative news, while liberals were suggested to underestimate support for the policies due to a false-uniqueness effect.
Another example of pluralistic ignorance is the tulip mania of 1634. It is a great example of how investors can be swept up in a financial frenzy due to collective illusion. The Dutch elite decided that having one's own unique collection of the spring flowering bulbs was an absolute necessity. So, despite the flower's lack of any intrinsic value, the prices began to rise.
Men's conceptions of how they are expected to conform to norms of masculinity present additional examples of pluralistic ignorance. Specifically, most college age men are uncomfortable with other men "bragging about sexual acts and giving details", but erroneously believe themselves to be in the minority for their discomfort. Similarly, college age men underestimate other men's "desire to make sure they have consent when sexually active". This "role-conflict" can have deleterious consequences for men's physical and mental health, as well as for society. Netflix's Derren Brown: The Push explores some aspects of these concepts. 
According to a 2020 study, the vast majority of young married men in Saudi Arabia express private beliefs in support of women working outside the home but they substantially underestimate the degree to which other similar men support it. Once they become informed about the widespread nature of the support, they increasingly help their wives obtain jobs.
According to a 2023 survey, most Americans do not prioritize college while believing most other Americans do. Similarly, the belief that society doesn't prioritize personally fulfilling work or that others desire a one-size-fits-all model of education is a collective illusion.
Pluralistic ignorance can arise due to various aspects of human interaction. These are three key causes of pluralistic ignorance when analyzing the phenomenon at the group level.
The conservative lag is the most common cause of pluralistic ignorance and has also been labeled as "conservative bias".  This cause refers to a change in attitude that is not then followed by a change in behavior. A popular example of a conservative lag would be the civil rights movement. Although there was a shift in the private opinions of White Americans toward African Americans and the practice of segregation, a shift in social norms and public behavior did not come until long after. This example of pluralistic ignorance demonstrates a valuable aspect of social change, "a society's perception of itself tends to lag behind actual changes in people's private beliefs and values".
A liberal leap is described as a change in behavior that is not then followed by a change in attitude. This cause is often associated with revolutions or polarizing events that shift the fabric of society, resulting in a change in behavior. A couple examples would be the shift in the French's public support of the Church in the 18th century, but their attitudes staying the same or the sexual revolution in America during the 60s and 70s that resulted in a change in public behavior and sexual expression, yet personal attitudes toward sexual behavior remained consistent.
This cause of pluralistic ignorance focuses on the correlation between one's social identity and their behavior in social settings. In an effort to conform to certain values, ideals, and norms, an individual's behavior may not align with their attitude or beliefs. This is commonly associated with studies involving gender norms, such as children choosing to play with toys and engage in activities that are associated with their biological gender, even when they may have an interest in something that doesn't fit the traditional expectation.
In recent years, pluralistic ignorance has been categorized as a roadblock to collective action involving important public issues, such as climate change and the COVID-19 pandemic.
Another consequence of pluralistic ignorance is groupthink. This refers to a situation where small, cohesive groups of intelligent individuals are led to make unintelligent decisions. Taking it a step further is the "illusion of unanimity", which describes a situation where an individual believes that they are the only one in the group that doesn't agree with the decision being made. Often times, this illusion causes individuals to embrace the decision, as bad as it may be, if they feel their disagreement is not shared with the other members of the group.
Perhaps the most researched consequence of pluralistic ignorance from an individualistic perspective is the bystander effect. In its most rudimentary form, the bystander effect describes a situation in which an individual is witnessing an event that prompts a strong set of emotions, yet they choose not to act on them since the surrounding "bystanders" are making no visible efforts to act, giving the impression that the individual's feelings toward the situation are invalid and not shared. This ultimately can result in a lack of action from everyone witnessing the event when action may be the appropriate choice given the situation.
Maintaining the perspective of the individual, pluralistic ignorance can also cause people to feel alienated from a specific group. When one's personal attitude is seemingly in contrast to the majority, if not all, of those in the group, it can cause the individual to become "embittered" and "suspicious of those around them". It may even motivate the individual to speak out against what is the perceived majority view or go completely silent.The most probable result is the conformity of the individual in the way they speak and behave, possibly to the point of changing their personal convictions, in what might be the inaccurately perceived majority opinion.
Pluralistic ignorance can be compared with the false consensus effect. In pluralistic ignorance, people privately disdain but publicly support a norm (or a belief), while the false consensus effect causes people to wrongly assume that most people think like they do, while in reality most people do not think like they do (and express the disagreement openly). For instance, pluralistic ignorance may lead students to drink alcohol excessively because they believe that everyone else does so, while in reality everyone else also wishes they could avoid binge drinking but no one expresses that wish out of fear of being ostracized. A false consensus for the same situation would mean that the student believes that most other people do not enjoy excessive drinking, while in fact most other people do enjoy that and openly express their opinion about it.
A study undertaken by Greene, House, and Ross used simple circumstantial questionnaires on Stanford undergrads to gather information on the false consensus effect. They compiled thoughts on the choice they felt people would or should make, considering traits such as shyness, cooperativeness, trust, and adventurousness. Studies found that when explaining their decisions, participants gauged choices based on what they explained as "people in general" and their idea of "typical" answers. For each of the stories those subjects said that they personally would follow a given behavioral alternative also tended to rate that alternative as relatively probable for "people in general": those subjects who claimed that they would reject the alternative tended to rate it as relatively improbable for "people in general". It was evident that the influence of the subjects' own behavior choice affected the estimates of commonness. Although it would seem as if the two are built on the same premise of social norms, they take two very oppositional stances on a similar phenomenon. The false consensus effect considers that in predicting an outcome, people will assume that the masses agree with their opinion and think the same way they do on an issue, whereas the opposite is true of pluralistic ignorance, where the individual does not agree with a certain action but go along with it anyway, believing that their view is not shared with the masses (which is usually untrue).
This phenomenon is similar to pluralistic ignorance in that it involves observing the differences in oneself compared to others, rather than the similarities. This observation of others is often negative, alluding to one's habit of viewing oneself as better at possessing positive characteristics when compared to those around them. Unlike pluralistic ignorance, false uniqueness effect is a distinctly individual phenomenon with no beginning or outcomes associated with group dynamics.
The parallel between pluralistic ignorance and the spiral of silence comes from their joint interest in the reasoning behind the shift in public opinion perceptions in relation to the public's genuine attitudes. When viewing pluralistic ignorance through a social perspective, one can assess how it is caused through misinformation that is shared broadly by those who are highly visible. This is where the concept of visibility becomes most important in understanding the intertwined web of pluralistic ignorance and the spiral of silence.
When a group stands out by way of making the most noise or causing the most chaos, this can give the impression that the group is more influential than they actually are. The spiraling process is initiated by the most visible and expressed opinions being shared loudly and publicly, while the genuine and differing opinions of the group are not expressed (or not on the same scale), causing a misleading depiction of the group's true attitudes and beliefs. Thus, pluralistic ignorance gives way to a shift in the climate of opinion, which then causes the spiral of silence to perpetuate as those who view their attitudes and beliefs as the minority opinion (when they might not be) choose to remain silent.