It was 1907 and Francis Galton – a British statistical, biologist and anthropologist – was in one cattle fair Where a competition was underway: estimate the weight of an ox. Galton noticed that the average estimate made by hundreds of people was incredibly close to real weight of the animal. Not only that: the collective error was much lower than the average one of the individual.
This is the principle of “wisdom of the crowd “: the idea that the collective judgment of a heterogeneous group can overcome that of an expert.
Galton used this example to support theExtension of the right to vote And give the people, the “crowd”, the right to express their individual opinion. Today this principle finds application in surveys, financial markets, bets and political decisions. The problem, however, is that Not all crowds are wise. To be, a crowd must be composed of Very different individualsmotivated to respond to the best and who do not influence each other. If these conditions do not occur, the crowd will tend to give the wrong answer.
We see the most famous example of wisdom of the crowd, what are the characteristics of a wise crowd and how the errors of the crowd influence our society.
Like a crowd he guessed the weight of an ox without weighing it
In the article published in the magazine Nature, Galton tells of how he was in Plymouth at a country fair when he came across a competition: hundreds of people had to Guess the weight of the meat that would be obtained from an ox. Each participant paid a small share to participate, wrote their esteem on a ticket and those who approached the more he would win the competition together with the flesh prize.
At the end of the competition, Galton collected the 787 estimates of the participants and ordered them from the lowest to the highest. Then took the central estimatemedian called, which has exactly half of the estimates above and half below. This era of 548 kg, only 5 kg more than the real weight animal (543 kg). The even more surprising data emerged when he calculated the average: 543.5 kg. Only half kg of difference with a real value.
Each individual, alone, had made much bigger errors, but crowdas a whole, he had been right. According to Galton, this was a good topic in favor of popular judgment. If the whole of middle citizens manages to estimate the weight of a better ox than a single expert, perhaps extending the right to vote to several people, better political results can be obtained. This theme was particularly relevant in the early twentieth century England, when the debate was underway for the extension of the right to vote and whether to consider popular opinion valid or not.
Because it works and how crazy wise are made
The idea behind the principle of wisdom of the crowd is simple: each individual judgment contains a part of useful information and a part of mistake. By putting many independent estimates together, errors tend to cancel themselves and information is combined, leading to a more precise response.
But to really work, the crowd must have some characteristics. Galton identified three main ones:
- Motivation: participants must be interested in giving the right answer. At the fair, everyone wanted to win the prize, did not give random answers and made their best.
- Independence: the components must not influence each other and must not be emotionally linked to the answer. At the fair, everyone decided for themselves, there was no comparison between the participants before writing on the ticket. Too much communication, or the pressure of the group, can distort the result.
- Aggregability: There must be a way to summarize the answers in a single common opinion. In the case of the fair they were the average and the median, in the democratic case it is the vote of the majority.
In these three conditions, two more have been added over time:
- Diversity: The different opinions, the more likely it is that the errors compensate. An heterogeneous group, with very different components, gives better answers than a homogeneous one, with very similar components.
- Absence of centralized control: a authority that guides or manipulates the answers must not be given to us.
When the crowd is wrong and because it often happens
The wisdom of the crowd has applications in many different areas: quiz (think of the famous “help of the public” of “Who wants to be a millionaire”), identification of online scams, political, economic, sporting and environmental predictions. Still, we know well that The crowds are not always wise. Anyone who has participated in an event or is part of a fans know: even intelligent people can make stupid decisions when they are part of a group. In theory, a wise crowd is made of individuals who reflect and decide independently. In practice, however, We are social animalsand we let ourselves be easily influenced by what others think and by the emotions of the moment.
A 2011 study showed that the forecast made by groups of American football fans were systematically distorted: the excessive affection For his team he led to overlook the chances of victory, moving away from the real results. Another 2019 study has shown that when people can see the opinions of others they tend to to align with consent Even if I disagree, and this worsens the quality of the overall response. It is theflock effect: We tend to follow the mass, but so the crowd stops giving intelligent answers.
These limits are even more evident on social networks. In theory, they would be perfect tools to collect large -scale heterogeneous opinions, creating a very wise “crowd”. In practice, they often strengthen the bubbles of thought and are vulnerable to external manipulations (BOT, fake accounts, piloted influencers), compromising the diversity and independence of opinions.
The best way to minimize errors, therefore, is Compare ourselves with many people, very different from us. Mathematics tells us.
