He talks about concentric circles of friends. These number 5, 15, 50 and 150. The last circle is the "Christmas card list", those people we touch base with about once a year. The inner circle of 5 friends (and only 4 if you are in a relationship) represents about half of our social time. When you take the first 2 circles of 15 people, this represents around three quarters of our social interactions. Dunbar talks about the number of friendships we can maintain being based on the size of our brain, in particular the social cognition circuit that lets us understand what others are thinking. He asks if it is possible for this part of the brain to expand during childhood, perhaps as a result of increased numbers of online friends, and concludes that this is possible, though only up to the age of 20. In general maintaining friendships takes a huge amount of time, as you need to invest time to get emotional closeness.
There are significant differences in males and females regarding how digital media can help maintain friendships. Women account for about 2/3 of time on Facebook. Men maintain friendships by doing things together rather than by talking. Women, on the other hand, maintain friendships through conversations, therefore social media can maintain close friendships in women. The most ideal technology for this is shown to be Skype, where there is a sense of co-presence and an immediate response.
I found this module of this week's course to be fascinating. I'm looking forward to next week which is about learning to think in a digital age, where we will consider how different ways of thinking and learning behaviour might be emerging from an immersion in digital devices.