Science News has a remarkably clear and concise article on a study that looked at how ideas spread through social networks. It found that under most circumstances a critical mass of more easily influenced people, not ‘opinion leaders’, are key to making ideas popular.
One of the major theories in marketing is that new ideas are taken up by the wider population because they are adopted by ‘opinion leaders’ – respected individuals who others listen to.
The theory goes that when opinion leaders adopt an idea, lots of other people quickly follow. Sort of like a ‘leader of the pack’ theory.
Researchers Duncan Watts and Peter Dodds wondered whether this was really the case, or whether instead, large numbers of people would embrace a particular idea when a certain number of their more easily influenced peers started to champion it. More of a ‘birds of a feather’ theory.
Watts and Dodds research how the mathematics of networks can tell us about how social systems work, and so they created various simulated social networks, set up some rules, and then ran the experiments to see how easily ideas would spread.
They simulated individual differences in the model by making each person more likely to adopt an idea if a certain percentage of their social network already believed it.
As some people are more easily influenced than others, the ‘people’ in the network varied in what percentage of their peers were needed to influence them – in effect, a mathematical simulation of individual scepticism.
The researchers compared how far an idea would spread depending on whether it started with a random individual or with an influential individual who was connected to a lot of other individuals. They found that highly influential individuals usually spread ideas more widely, but not very much more widely. For example, if an individual had three times as many connections as the average person, ideas espoused by that individual almost always spread substantially less than three times as far as the ideas of an average individual. Sometimes, the researchers found, the difference wasn’t even measurable…
More important than the influencers, the researchers found, were the influenced. Once an idea spread to a critical mass of easily influenced individuals, it took hold and continued to spread to other easily influenced individuals. In some networks, it was far easier to get an idea established this way than in others. The entire structure of the network mattered, not just the few influential people.
The full-text of Watts and Dodds’ paper is available online as a pdf if you want to read the study in more detail, but the Science News article is a great summary.