Source: David Lienemann (Public Domain)

When Joe Biden announced his candidacy for the Presidency of the United States on the 25th of April, 2019 many considered him to be the front runner and the most likely candidate to succeed. Over the last 10 months, however, Biden sunk in favour —delivering less than stellar performances in the Democratic Primary Debates, and not even making it into the top three of some polls in 2020.

But everything changed with the 2020 South Carolina Democratic primary in which Biden received a big victory. Many of his former competitors, such as Pete Buttigieg, Amy Klobuchar, Michael Bloomberg, Beto O'Rourke, Kamala Harris, Cory Booker, Andrew Yang, John Delaney, and Deval Patrick, despite their attacks on him in the debates, decided to endorse him.

Prior to that, Bernie Sanders was considered the most likely candidate to win the nomination. Yet, Biden won 10 out of 14 states on Super Tuesday, the day with the greatest number of states holding their elections simultaneously. Victories in Texas and Michigan that were predicted to be won by Bernie Sanders cemented the picture that it will be the job of Joe Biden to face off against Trump in the 2020 Presidential Race.

But how did he do it?

The reason isn't some elaborate political trick. No, it is a phenomenon that has been extensively studied in economics, psychology, and political science: it is the 'Bandwagon Effect'. In a previous article I have defined the effect as follows:

"economics, psychology, and political science describes the 'bandwagon effect' - or alternatively 'contagion effect' - as a general cultural phenomenon or in which the rate at which the spread of ideas, behaviour, and trends more generally, rises with the rate of others adopting the trend" - Walter Veit (2020)

Though the idea is often only vaguely expressed, there is a real psychological phenomenon here that has led many to complain about political outcomes being decided in advance through surveys and polls. After the surprising victory of in 2016 this effect has come to be disregarded, yet it not only explains the 'underdog' victory of Trump, but also the surprising return of Joe Biden.

Indeed, similarly to Trump, Joe Biden has had the most media coverage and familiarity among voters from the very beginning. In a field of many candidates, the primary problem becomes one of standing out among others.

For Democrats, especially the moderates among them, there was a consolidation problem in deciding who to endorse. In a field with progressives such as Bernie Sanders and Elizabeth Warren, moderate Democrats were scrambling for votes amongst each other. The victory of Joe Biden in the South Carolina Democratic primary sent a signal for all the others to unify behind him. Had this decisive victory gone to any other of the moderate candidates we might be looking at a very different field now. It thus need not be a sign of the quality of Biden's candidacy, but rather an instance of the Bandwagon Effect. An easy analogy suggests itself from the success and failure of restaurants that might be based entirely based on chance, rather than their quality:

"Another potential human example would be two empty Indian restaurants with big windows next to each other. We might have no initial reason to prefer one over the other. But now we see a customer entering one of them. This might reveal information about the quality of the restaurant and hence we would follow. Yet, this need not always be the case. The first customer may very well have chosen randomly, and thus picked an objectively worse restaurant. Yet, others might follow his lead - thus leading to the success of the objectively worse restaurant. This is why it is called the bandwagon effect, a potential bias that can lead to surprising collective behaviour that need not always be beneficial or rational." - Walter Veit (2020)

Our human psychology is quick to rationalize victories. If someone succeeds we do not treat it as a mere matter of chance but look out for other features that differ between winners and losers. Yet, as much of history reveals, many of the greatest wins and losses came down to small chance events. The earliest primary elections can have large snowball effects down the line. The outcome of these elections may have nothing to do with the general quality of a candidate.

This is not to say that Joe Biden wouldn't be a good candidate, nor that he has special features that will help him against Trump—but it is a recognition that human psychology and herding behaviour plays a large part in the realm of .

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