Why has HIV spread so rapidly through the world’s population but behaviours that can prevent HIV have not? As the world is in the grip of a potential pandemic, this question raised by Damon Centola in his book How Behavior Spreads: The Science Of Complex Contagions is of great signifiance. Damon relies on the “strong ties, weak ties" framework developed by Mark Granovetter, an American anthropologist, to explain the spread of information, diseases and behaviours.
According to Granovetter, relationships in a social network are characterized by strong ties, weak ties or absent ties. A strong tie is a connection with someone within a close-knit network of family and friends. A weak tie is a link with a casual acquaintance. One’s weak ties are spread far and wide. In a famous article, Strength Of Weak Ties,that appeared in American Journal Of Sociology, Granovetter contended that weak ties are ideal for the fast diffusion of information across a larger population. For the same reason, diseases too spread fast and wide through weak ties. But behaviours tend not to travel across weak ties.
In public health settings, there are two types of behaviours. The first are once-and-done behaviours, like getting a polio vaccination, where a single shot keeps the disease away for life. But many public health problems can be solved only if people sustain a behaviour over a period of time, like using a condom for HIV prevention or washing hands to prevent the spread of covid-19. Public health officials across the world know that instilling once-and-done behaviour itself is difficult. Instilling repeat behaviour is an even bigger task.
An idea of how new behaviours are widely adopted by a society is offered by Roger Gould’s study of the Paris Commune revolts, Doug McAdam and Ronnelle Paulsen’s study of the Freedom Summer, civil rights activists’ fight for to the voting rights of minorities in the US, and a study of the spread of trade unionization in Northern Europe. These social movements drew strength largely from strong spatial ties.
In public health settings too, spatial networks are the primary pathways for the adoption of innovative behaviours. Any new behaviour is met with lot of hesitation and scepticism. In these uncertain times, confirmation from several others adopting the same behaviour acts as a big incentive to adopt or maintain that new behaviour. A good example of behaviourial change using social contagion is the Korean government’s contraception initiative of the 1960s. Its effectiveness hinged on villagers getting local exposure to contraceptive choices through contact with their neighbours. Women tended to adopt the same methods of contraception as their personal contacts. There were diverse modes in use across the country at the time, but there was uniformity in the method being used within each village.
Although the medium of strong spatial ties is ideal for effective behaviour diffusion, the speed at which this works is slow. Unless the pace of behaviour diffusion catches up with that at which a disease spreads, we would be fighting a losing public health battle. An option is to use weak ties within social networks to increase the speed of behaviour diffusion.
Weak ties have a far wider spread. But they exist in public places like airports, offices, schools and religious congregations. Public spaces are also the likeliest where a disease is transmitted across weak ties. A recent Massachusetts Institute of Technology (MIT) study showed that only about 20% of people at airports have clean hands, and other 80% are potentially contaminating everything they touch with whatever germs they may be carrying. Focused interventions in just 10 of the world’s leading airports to instil the habit of washing hands could potentially slow the spread of some diseases by as much as 37%, the MIT researchers estimate. So, the introduction of appropriate new behaviours like washing hands and wearing face masks in congregational spaces could go a long way in preventing the spread of diseases. Some social sanctions could be imposed on those not following these new behaviours. The habits inculcated in these public places have a great chance of being adopted in one’s personal spaces too.
Social media is an ideal medium to connect with one’s weak ties. Many social media groups are formed among people who are similar to one another in some ways. In uncertain situations, humans tend to follow the behaviours of those who seem similar to us. So, Damon Centola has found that social media groups could be converted into clustered networks for the social reinforcement of new behaviours. As more people join online networks, more opportunities emerge for this exercise. A smart digital strategy can be used to convert weak ties into effective pathways to spread a new behaviour.
Creating a certain level of panic does help raise the rate at which new behaviours are created and maintained. After all, the emotion of fear has saved far more human lives than even modern medicine. A judicious use of panic should thus become an integral part of any disease management strategy. It may be a good initiative to reduce the number of testing centres in the early stages of a disease’s contagion. The panic generated by such a scarcity would make even those with the slightest suspicion of having its symptoms rush to a testing centre. This would help contain the spread of disease in its early stages.
Traditionally, during a public health crisis, there has been a tendency for public policy to focus on creating awareness campaigns. A strategy based on generating greater awareness has not helped much in developing appropriate new behaviours, however. Instead of the conventional campaigns that aim to provide information, the focus should be on activating weak ties in a society to alter behaviour patterns. The very connections that spread the disease should be used to make people behave in ways that will help reduce contagion levels. That is the real strength of weak ties.
Biju Dominic is the chief executive officer of Final Mile Consulting, a behaviour architecture firm