I’ve been thinking about social capital recently, so was eager to read Matthew Jackson’s The Human Network: How We’re Connected and Why it Matters. This is the version of his terrific work on networks and social capital (for example Social and Economic Networks (2010)) aimed at a general readership. Although the book starts with some of the concepts of network theory, it uses diagrams rather than equations to explain. (Anyone wanting a slightly more technical introduction to network theory needs to go elsewhere. Perhaps Barabasi’s Linked, as a still reasonably accessible read.)
Above all, The Human Network motivates the use of the network lens on economic and social questions, from epidemics to the diffusion of technology to financial crises to social immobility. Why did one long-discredited individual who made up his results for a 1998 article manage to trigger an anti-vaccination movement which is still leading to epidemics of infectious disease? What is the difference between a financial system that diversifies risk and one that concentrates it? Why are social media influencers a thing?
The Human Network is a very engaging and worthwhile read. I was for the most part familiar with the material it covers, but nevertheless enjoyed reading it, and also gained some insights about the different ways information can cascade through a network, either amplifying a single (possibly incorrect) piece of information, or pooling different sources of information for a more accurate picture. Given that our societies are highly interconnected in vast networks, and saturated with sources of information through online media, understanding the way networks function seems essential. One would hope at least public health authorities (to deal with epidemics) and financial regulators (to monitor the risk of systemic crisis) have their network diagrams at the ready. One of the messages I came away with is how easy it is for epidemics, real or metaphorical, to spread in the modern world of six degrees (or fewer) of separation.