I think both Dunbar and Morgan are right. It’s critical that we pay attention to that 150 number for our “survival” community in close proximity. If we don’t feel we have that “tribe” near us it causes us to feel alienated, isolated and stressed. Perhaps one of the reasons social media is so popular, and so many of us rely on Facebook and Twitter is that we don’t have a strong tie tribe. Although the weak tie network of social media helps us to feel connected, we’ll eventually feel let down if we try to have it substitute for a strong tie Dunbar tribe.

https://www.blog.theteamw.com/2010/03/24/100-things-you-should-know-about-people-30-our-strong-tie-group-size-is-150-people/