Did cheap travel and communication, in combination with the Dunbar number, lead to larger bubbles and greater epistemic fragility?

From Links to Consider, 2/16 by Arnold Kling.  

A podcast with Yascha Mounk and Ricardo Hausmann. Hausmann says,

we know many, many more people from farther and farther away that are closer to our areas of intellectual interest. And we know less and less people who are farther away from our areas of intellectual interest. In the good old days, it was kind of required, expected. It was a social norm that you would go to church. And in church, you would find different segments of society sharing an experience. And that experience, in some sense, reminded everybody that they were in contact with one another, that they were dependent somehow on one another.

They discuss themes that I emphasize in Specialization and Trade and in my writing here. The passage above is in the midst of a discussion of how most people were “somewheres” (closely tied to a particular place) before the modern era. That produces more local solidarity but less specialization and trade. Today, we are richer but less engaged with our neighbors.

An interesting insight about churches serving an integrative effect both in terms of class and in terms of locality.  

I would add that there is a Dunbar Number effect to be considered.   If we are indeed constrained to something like 150 stable relationships, then the implication is that when travel and communication are expensive, then it is probably that the bulk of those 150 stable relationships will be more local and more diverse (less specialized.)

As the cost of travel and the cost of communication falls, the viability of maintaining long distance relationships with affiliative homophilic attributes increases.  It is not just that we are able to build a bigger bubble of specialization.  It is that a larger portion of our 150 limit can now be taken up with that specialization.

If, in the 1960s and 70s it is expensive to travel and to communicate, then it might be the case that 50 of your 150 stable relationships are in some way related to your core interests/profession.  If the cost of travel and communication falls dramatically (as it did), by 2020, perhaps 100 of your 150 stable relationships are now related to your core interests/profession.  

What are the implications of a bigger bubble of lower locality and class variability?

Perhaps epistemic fragility?  Tetlock's work suggests that the most effective forecasting and integration of knowledge occurs among intelligent generalists.  Their forecasts are more accurate than those of experts because they are able to integrate a more complete comprehension of all the factors affecting the forecast.  Experts tend to produce attenuated forecasts because their narrow knowledge is excellent but undermined by having weaker contextual knowledge.

Further, experts tend to be more passionately and confidently committed to their forecasts than are generalists.  

Perhaps the implication of cheap travel and communication leading to bigger bubbles with less class and locality variability is the rise of more passionate commitment to less accurate forecasts.  That is an interesting thought and certainly consistent with the mainstream media presentation of polarization and conflict despite the great bulk of people living more prosperous, safer and stable lives than at any time in the past.