Short answers, pulled from the story.
Pluralistic ignorance is a phenomenon in which people mistakenly believe that others predominantly hold an opinion different from their own. As a result, many members of a group publicly go along with a view they privately reject, because they incorrectly assume that most others support it. The term was first introduced in Floyd Allport and Daniel Katz's 1931 book Students Attitudes: A Report of the Syracuse University Research Study.
Floyd Allport first discussed the underlying phenomenon in 1924, calling it "literal attitude behavior inconsistency." The term "pluralistic ignorance" itself first appeared in the 1931 book Students Attitudes: A Report of the Syracuse University Research Study, co-written by Allport and his student Daniel Katz.
A survey of 6,119 representatively sampled Americans published in Nature Communications in August 2022 found that 66-80 percent supported major climate-mitigation policies, but 80-90 percent of those same respondents underestimated how widespread that support was. Respondents in every state and demographic group underestimated support by at least 20 percentage points. Globally, studies find that 80-89 percent of people want governments to do more on climate change, yet most believe they are in the minority, estimating only around 30 percent support stronger action.
Three causes are commonly identified. The conservative lag occurs when private attitudes shift but public behavior does not follow, as seen in the civil rights movement in the United States. The liberal leap occurs when behavior changes without a corresponding change in attitudes, as with the sexual revolution in the United States during the 1960s and 1970s. The third cause is social identity, where individuals conform to group norms even when their private beliefs differ.
In pluralistic ignorance, people privately reject a norm or belief but publicly go along with it, assuming that others genuinely hold it. In the false consensus effect, people wrongly assume that most others share their own view and openly express it. A study by Ross, Greene, and House using Stanford undergraduates found that participants consistently estimated that others would make the same choices they themselves made.
Consequences include the bystander effect, in which individuals fail to intervene in a situation because others' inaction signals that no response is needed. Groupthink is another consequence, in which small cohesive groups make poor decisions when members stay silent, believing their private doubts are not shared. Pluralistic ignorance has also been proposed as a factor in the illusory support that kept the Communist Party of the Soviet Union in power, and in recent years as a barrier to collective action on climate change and a driver of far-right party growth.