Disassociation
Social disassociation is equivalent to being alone in a crowd; where one makes the appearance. It is what was called "making the scene," but with minimal human interaction. This is nothing new as we can see from these old photos and it's even more prevalent today as each person is totally engrossed with their smart phones. I find it odd that in a group of people walking or sitting around most are on their smart phones communicating with others not present. What little human contact there is is now being more diluted so that this process becomes even more pronounced. Anomie? Perhaps that's what it's meant by this term. No personal contact...well it's just too much of a commitment these days. No entanglements, keep it simple, no one gets emotionally damaged this way.