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Full Version: Why Dunbar's number has not been debunked?
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https://theconversation.com/dunbars-numb...iny-160676

INTRO: Exactly 30 years ago, I was pondering a graph of primate group sizes plotted against the size of their brains: the larger the brain, the larger the group size. I was curious to know what group size this relationship might predict for humans.

The number my calculations gave was 150. Since this seemed low, I hurried off to the library to look for data on natural human group sizes. Hunter-gatherers live in multilevel societies, with groupings of individuals forming a hierarchically layered structure – families within bands, bands within communities, communities within tribes.

The community level of organisation turned out to be almost exactly 150. Thus was born the “social brain hypothesis” and “Dunbar’s number”, the former referring to the relationship between group size and brain size in primates and the latter referring to the natural group size of about 150 for humans.

Dunbar’s number has attracted a great deal of attention over the years. For example, it has been used in the design of social media platforms, as well as being the basis of “secret handshake” online security algorithms and bot-detection software.

Architects have mulled over its application to building design, and there has been considerable interest in the world of business, for whom it resonates strongly. “Dunbar_number” yields nearly 1,400 papers on Google Scholar, and 26,500,000 hits on Google.

This exposure has, perhaps inevitably, led researchers to challenge Dunbar’s number. In science, challenges are helpful: they force us to evaluate the assumptions underlying a hypothesis and, as a result, invariably point the way to new discoveries. This hasn’t always been true for Dunbar’s number: most of the critiques have just muddied the waters.

Despite the growing evidence, the same critiques reappear with suspiciously religious zeal. The most common claim is that human behaviour is culturally determined and so cannot be subject to the same biological rules as primate behaviour. Another variant on this claim is that networking platforms such as LinkedIn have made it possible for us to maintain more extensive social networks.

Most of these claims fail to recognise that Dunbar’s number applies to quality relationships, not to acquaintances – which account for the more casual outer layers of our social networks, beyond our 150 meaningful friendships.

However, a more recent challenge by researchers at Stockholm University claims to have finally debunked Dunbar’s number by showing that the social brain equation underpredicts human social group sizes. Alas, the study used flawed statistical methods and fails to account for the body of evidence we now have to support Dunbar’s number... (MORE)