Go forth and multiply

These days, “influencer marketing” is a must-have component of any brand strategy. Propelled by the reach of online channels like TikTok and Instagram, the approach feels like a modern-day phenomenon. However, the principles that underpin it are far from new. The influence of opinion leaders in the spread of innovation is highlighted by a 1960s’ study into the introduction of modern math in Pennsylvania. This study, now almost 60 years old, provides an education in the power of opinion leadership.

In the late 1950s, top mathematicians in the US proposed a radical overhaul of the public-school curriculum through the introduction of “modern math.” The new approach, which emphasised concepts like Venn diagrams, algebra, and probability, was heavily endorsed by federal bodies including the US Department of Education.

In 1965, researcher Richard Carlson studied the diffusion of modern math among 38 school superintendents in Allegheny County, Pittsburgh. The study examined the influence of opinion leaders in the spread of the new curriculum from school to school. Personal interviews sought to establish what year they had adopted modern math, and which other superintendents were their ‘best friends’. The aim was to understand the diffusion network.

According to the study, the adoption of modern math in Allegheny County began with a single superintendent in 1958 – an ‘innovator’ who travelled from outside the Pittsburgh area and had no links with any of other 37 superintendents in the local network.

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“Opinion leaders generally conform to the norms of their local system, making them more credible and influential than cosmopolite innovators.”

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Carlson’s study mapped the communications network of the 38 superintendents, highlighting a central clique of six friends who regularly engaged in social activities. This group, which included the three most influential opinion leaders in the system, was pivotal in the spread of modern math. Once these opinion leaders adopted modern math the diffusion process accelerated.

It’s a classic story by numbers. In 1958, only one superintendent – the innovator – adopted modern math. But by the end of 1960 – after all three key opinion leaders had adopted – that number had risen to 15. It grew to 27 in 1961, 35 in 1962, and all 38 by 1963. The rapid adoption phase was directly influenced by the opinion leaders’ endorsement.

According to diffusion experts, opinion leaders generally conform to the norms of their local system, making them more credible and influential than cosmopolite innovators, who may be viewed as too radical. In the case of Allegheny County schools, the superintendents waited for the opinion leaders’ acceptance of modern math before adopting it themselves, indicating the importance of these local influencers in the diffusion process.

So, what can we learn from US math teachers from the 1960s? The equation is simple: for effective diffusion of innovation, change agents should focus on gaining the support of opinion leaders. These influencers can significantly amplify promotional efforts due to their prominent position within their social networks.