There is a lot of concern in the media and political circles about the effects of poll results on voters. In late September, when Obama was dominating the polls, Republicans latched onto the idea that the polling industry was skewing polls in Obama's favor to give him the air of inevitability. When Gallup's likely voter model later gave Romney a 7 point lead in mid-October, everyone started wondering not only what this meant about the election, but if could affect the election.

Finally, in a quiet period during the morning after the final presidential debate, the price of the contract for Mitt Romney to win the election escalated rapidly on Intrade, only to retreat back down almost as quickly. Had someone tried to manipulate the contract to make it appear that Romney won the debate or that the election was suddenly tied? Would that be a rational use of money?

To answer the burning question, researchers have long observed that people often conform to majority opinion (i.e. during every election, some people jump on the bandwagon and shift their preference to the leading candidate or the most popular policy).

During elections, and major public policy events, much of the media coverage focuses on the "horse race," or fluctuations in support for a candidate or policy. Reporting on public opinion not only affects support, but levels of engagement: donations, volunteering and turnout. These bandwagon effects can make polls self-fulfilling prophecies; the predictions of the polls come to pass because the polls not only measure public opinion but also influence public opinion and engagement.

While numerous studies have documented the existence of the bandwagon effect in the political domain, very few have attempted to understand the underlying mechanisms of why people conform to prevailing popular opinion. Researchers generally posit two psychological mechanisms underlying conformity: (1) people's desire to adopt the majority position so as to feel liked and accepted or believe they share the prevailing opinions of their community (i.e., social acceptance); and (2) people learn from the "wisdom of crowds," or assume that other people did the research so their collective wisdom indicates something about the quality of the candidate or platform (i.e., social learning).

Research that I conducted with Neil Malhotra of Stanford University also examines a third mechanism: polls reveal information about the likelihood of a policy passing or the election of a candidate, so people resolve cognitive dissonance ("Policy X is going to pass, but Policy X makes me unhappy") by switching to the side they believe is going to win.

We conducted an experiment on a nationally representative sample of voters in 2011 which simultaneously tests these three mechanisms to assess which are more powerful drivers of the bandwagon effect, or conformity to majority public opinion in politics. We do not suggest that these three mechanisms are collectively exhaustive or mutually exclusive, but due to their prevalence as broader psychological phenomena, they offer a promising direction to begin investigation.

Confirming past studies, we find strong evidence of an overall bandwagon effect; people become more supportive of policies that have more general support. We further find that both social acceptance and social learning drive the bandwagon effect. However, the effect of social learning is significantly and substantially stronger than that of social acceptance. Thus, the main reason that people conform to majority opinion in the political domain is that they believe there is information about the quality of the candidates or policies to be learned from mass support. We find no evidence for the third mechanism -- that people conform because they want to reduce cognitive dissonance related to not supporting a candidate that will likely win or policy that will likely be implemented.

The idea of the bandwagon effect seems disheartening for democracy if conformity pressures silence minority opinions. However, this research has given us a reason for optimism; people seem to be conforming not only because they see normative value in being part of the majority but also because they believe that there is information in collective opinion. Citizens want to be informed and the collective wisdom of their fellow citizens is just one source of information on which they have learned to rely.