What is the bandwagon effect?
The phrase has three owners: an economist's demand curve, the pollster's survey experiment and the music-download study. What each one measured is not the same thing.
Answer to the question
What is the bandwagon effect?
The bandwagon effect is the tendency for something to gain support because others already support it. Leibenstein defined it for market demand in 1950, and later studies of polls, music downloads and online ratings found it real but dependent on the setting, with some people moving the other way.
Key takeaways
- Leibenstein (1950) defined the bandwagon effect as the extent to which demand for a commodity rises because others are also consuming it, in a paper of demand theory with no experiment.
- Nadeau and two co-authors (1993) report a bandwagon effect of roughly 5 to 7 per cent on abortion and the constitutional future of Quebec, from a design that allowed for underdogging.
- Rothschild and Malhotra (2014) found that poll information shifted attitudes on three public policies, with the size of the shift depending on the issue.
- Salganik and colleagues (2006) had 14,341 participants download unknown songs; stronger social influence increased both inequality and unpredictability of success.
- Muchnik and co-authors (2013) found a positive first rating raised positive ratings by 32 per cent and final ratings by 25 per cent on average, while a negative first rating was corrected.
A bandwagon was a wagon that carried a band, and in American election campaigns to jump on it was to join the procession. The bandwagon effect is what the phrase became: something gains support because others already support it. Economists use the name for demand that rises with other people's buying, pollsters for opinion that moves after a published poll, and researchers of online ratings for the way early votes steer later ones. These are three claims under one label. The first, Leibenstein's, is a piece of economic theory from 1950, and the other two rest on experiments run decades later.
What did Leibenstein's demand curve become in polling?
The economist Harvey Leibenstein gave the bandwagon effect its first formal definition in 1950. In his paper on bandwagon, snob and Veblen effects, it is the extent to which demand for a commodity rises because others are also consuming it (Quarterly Journal of Economics). The snob effect is its mirror: demand falls as others buy, because the buyer wants to stand apart from the crowd. The Veblen effect, the third of his trio, ties demand to price instead, and The Veblen Effect Is Mostly Folklore looks at how well it holds up.
Leibenstein defined the bandwagon effect as demand rising because other people also consume the good.
The paper is demand theory, not an experiment. It shows how a market demand curve would bend if each buyer's demand depended on what other buyers did, and it does not say why a buyer's demand should rise with other people's. Later researchers kept the name and tested something else: whether learning what other people think moves a person's own view.
In a 1993 study for the International Political Science Review, Richard Nadeau and two co-authors used a panel design alongside an experiment in which respondents were told the state and direction of public opinion. The issues were abortion and the constitutional future of Quebec. The authors built the test to allow for "underdogging" and for opinion shifts with other causes, and they report a bandwagon effect of roughly 5 to 7 per cent on both issues. They add that the reasons for it remain unclear.
An earlier panel study from the same team followed student groups' opinions on North American free trade. Exposure to a majority trend produced both bandwagon and underdog effects, which the authors attribute partly to the stimulus and partly to people's efforts to keep their opinions consistent. A poll that pulls some respondents toward the leader and pushes others away can leave the net movement small, and a design that records only the pull will overstate the bandwagon effect. The 5 to 7 per cent reported above comes from a design that allowed for the underdog response.
A national experiment published in 2014 arrived at a similar place by a wider route. David Rothschild and Neil Malhotra randomly assigned a diverse national sample to receive information about different levels of support for three public policies. Opinion as expressed through polls shifted individual attitudes, although the size of the shift depended on the issue. They described the existing empirical literature on the bandwagon effects of polls as "surprisingly limited".
Songs and comments show the same pull on rankings
Cultural markets give a version in which the crowd's choices are visible and consequential. In a 2006 Science experiment, Matthew Salganik and colleagues had 14,341 participants listen to and download previously unknown songs, some of them able to see how often earlier participants had downloaded each one. The market was run as parallel worlds, so the same songs met the same field repeatedly with different crowds. Here the bandwagon effect shows up in rankings: stronger social influence increased both the inequality and the unpredictability of success.
Quality only partly determined outcomes. The best songs rarely did poorly and the worst rarely did well, but other outcomes were possible. The market was artificial, which limits the study to what visible downloads can do under control, not how any real chart behaved. The longer account is in Why the Best Song Does Not Win.
Lev Muchnik and two co-authors tested the same logic in 2013 on a social news aggregator, where they manipulated the first rating a comment received. A positive first rating increased positive ratings by 32 per cent and raised final ratings by 25 per cent on average, while a negative first rating was corrected by later readers.
In that setting the bandwagon effect ran in one direction only: approval spread, disapproval did not. The authors report that the positive herding depended on the topic and on whether readers saw opinions from friends or from enemies.
Is following the crowd really a mistake by the follower?
Michelle Baddeley, an economist, argues in Copycats and Contrarians (2018) that following is often a sound inference. Of a restaurant queue in which each diner copies the diners ahead, she writes that following others is not necessarily irrational. Her objection to herds lies elsewhere. Even when the herd is on the right track, private information of value is lost when people disregard it, and the group bears that loss.
Baddeley argues that copying others can be a sound inference, not a mistake.
She extends the same reasoning to speculative bubbles. Paying a high price today is not stupid, she writes, if there is a good chance of selling to someone else at a higher price tomorrow. The mechanism is set out in When Copying Is the Rational Move and tested at the restaurant door in Does a Long Queue Make People Want In.
The bandwagon effect, on this account, describes what happens and leaves open whether the people doing it are being foolish. A crowd that holds good information makes a good guide, and the cost appears only when each follower discards what they knew.
Leibenstein wrote the effect as a property of a demand curve. The name then travelled to opinion polls, where the reported shifts depend on the issue, and to music downloads and comment scores, where the shifts are large and sometimes lopsided. The evidence changed with each move, from a theoretical curve, to survey shifts that vary by issue, to rankings that settle differently in every run of the market.
Common questions
What is the bandwagon effect?
It is the tendency for something to gain support because others already support it. Harvey Leibenstein defined it in 1950 as the extent to which demand for a commodity rises because others are also consuming it, and later studies of polls, music downloads and online ratings found it real but dependent on the setting.
Is the bandwagon effect the same as social proof?
They overlap. Social proof is Robert Cialdini's name for people looking at what others do and copying it when unsure. The bandwagon effect names the resulting growth in support for an option as support accumulates. Studies of poll effects and rating manipulations use the second term and measure the shift in support, not the reasons behind it.
Does the bandwagon effect mean people are irrational?
Not by itself. Baddeley's restaurant-queue example shows copying that is reasonable given what each person knows, and the cost she identifies falls on the group, which loses the private information each follower set aside.
Sources
Baddeley, M. (2018). Copycats and Contrarians: Why We Follow Others ... and When We Don't. Yale University Press. Seed book; vault hub Books/Copycats and Contrarians.
Cloutier, E., Nadeau, R., & Guay, J. (1989). “Bandwagoning and underdogging on North-American free trade: A quasi-experimental panel study of opinion movement.” International Journal of Public Opinion Research, 1(3), 206-220. doi:10.1093/ijpor/1.3.206 https://doi.org/10.1093/ijpor/1.3.206
Leibenstein, H. (1950). “Bandwagon, snob, and Veblen effects in the theory of consumers' demand.” Quarterly Journal of Economics, 64(2), 183-207. doi:10.2307/1882692 https://doi.org/10.2307/1882692
Muchnik, L., Aral, S., & Taylor, S. J. (2013). “Social influence bias: A randomized experiment.” Science, 341(6146), 647-651. doi:10.1126/science.1240466 https://doi.org/10.1126/science.1240466
Nadeau, R., Cloutier, E., & Guay, J.-H. (1993). “New evidence about the existence of a bandwagon effect in the opinion formation process.” International Political Science Review, 14(2), 203-213. doi:10.1177/019251219301400204 https://doi.org/10.1177/019251219301400204
Rothschild, D., & Malhotra, N. (2014). “Are public opinion polls self-fulfilling prophecies?” Research & Politics, 1(2). doi:10.1177/2053168014547667 https://doi.org/10.1177/2053168014547667
Salganik, M. J., Dodds, P. S., & Watts, D. J. (2006). “Experimental study of inequality and unpredictability in an artificial cultural market.” Science, 311(5762), 854-856. doi:10.1126/science.1121066 https://doi.org/10.1126/science.1121066