I was not thrilled by the reasoning presented here:<p>&gt; The team also point out that 2007 is a good year to look for Dunbar layers because it predates the widespread use of smartphones and social networks like Facebook. These provide other avenues for social contact that would have made the study much harder.<p>That&#x27;s not... a good thing to be bragging about if you&#x27;re trying to make a point.<p>First of all, this doesn&#x27;t acknowledge that lots of people don&#x27;t like talking on the phone. Further, lots of the closeness that creates intimacy between people can only happen in person. The more I like you, the less I want to spend my time with you on the phone.<p>The huge problem is that by controlling for Facebook and smartphones, you&#x27;re ignoring the fact that those technologies have completely re-written the communications story for our species in under a decade. Not to mention that there&#x27;s an entire generation that have come up at a time where texting and Facebook have always been there, so to exclude these mediums renders all of these conclusions not as analysis of how people communicate today but a record of how some people used to communicate in a previous era. It&#x27;s not useful, it&#x27;s cultural history.<p>The questions that are far more interesting now are around whether things like social media have started to affect our capacity for meaningful relationships. Surely while some of this stuff is biology, some of it was also a function of it simply being harder to keep in contact with 1000 people before 2007 for most people.