A Psychological Analysis of Strangers and Hospitality, Part 3: Hospitality and Our Moral Bandwidth

150.

When you get right down to it, that's the problem.

150.

i.
One of the most famous papers in cognitive psychology is George Miller's paper concerning the capacity of short-term memory. The paper was entitled The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information. Miller's research was important in establishing the capacity or bandwidth of short-term memory. We can hold about seven (plus or minus two) pieces of information in short-term memory without any mnemonic device. About the length of a phone number. Most people given a phone number can hold it in memory and repeat it back. Past 10 digits you start seeing significant memory errors.

I'd like to use The Magical Number Seven to suggest that diverse lines of research are converging upon a different kind of magic number. This number seems to be associated with our moral capacity, our moral bandwidth. It is the number that identifies the number of people we tend to count as "family and friends," the people I pull out from the world of "strangers" as worthy of altruistic attention. This Magical Moral Number isn't seven. The Magical Moral Number appears to be around 150.

How are psychologists coming up with this number? Well, to begin, if the brain has an adaptive history we can expect the information-processing faculties of the brain to display certain biases associated with the adaptive challenges the brain faced during that history. Adaptive pressures tend to produce conservative solutions in organisms. Take memory again as an example. For whatever reason the brain didn't invest massive amounts into short-term memory. Apparently, long-term memory was more important that short-term memory. Which makes sense. So the brain is like an investment banker, it has finite resources and has to allocate them according to adaptive need. It is true that these investments can be changed through experiences. The left hand of an expert guitar player has more neurons devoted to it than do non-guitar players. Experience does rewire the brain. But this plasticity isn't infinite in scope. There are constraints. You don't want the brain taking away connections from, let's say, the neurons controlling your heartrate.

When it comes to our innate moral psychology we see something similar to what we observed with memory. Upon birth and throughout development the brain needs to be able to identify and recognize the people inhabiting its social world. We saw this in the last post. The brain carves the world into "family and friends" versus "strangers." The question is how big can the "family and friends" group get?

Given that the brain spent most of its adaptive history in small, kin-related hunting-gathering bands it seems reasonable that the brain, like with short term memory, would not devote infinite memory resources to keep track of all social relations. It seems reasonable to expect that the brain would allocate memory resources to the social faculty of the brain that roughly correlated with the size of these hunting-gathering bands. There would be no real need for the brain to devote memory resources past this point. Thus, it is argued, the brain developed a moral/social bandwidth, it has a natural limit to how large the family/friends group will be. The limit roughly correlates with the actual size the family/friend group found during most of the brain's adaptive history. And how big were those hunting-gathering bands? Most anthropologists have it around 150.

This number grows more intriguing given the following:

If we correlate size of neocortex and social group size in the animal kingdom we find a regular positive trend: As group size grows so does neocortex. You need more brain to remember agents in your social groups as well as a memory for all the "relationships" in the group (who hates who, etc.). For primates like chimps the group size is 55. Extrapolating from human cortical size our social groups should be...you guessed it...150.

The average of number of Christmas card lists tends to be around 150.

The average number of entries on personal address books is around 150.

Organizations under 150 can be managed via face to face interactions without creating an organizational hierarchy.

The size of a military company, the basic military unit, where face-to-face command and communication is used, is between 75 and 200.

The point is, humans appear to have a social and moral bandwidth of about 150. Our memories can keep track of groups about this size. Beyond it our interactions become more anonymous. Past a group size of 150 we start needing formal organizational structures to handle interactions. Further, the group we consider "friends and family" clusters around this size.

ii.
So our brains have a natural moral capacity of 150. Given the Christian call live in a world without strangers this creates a bit of a bandwidth problem. We are constantly fighting an inclination to focus our love and welcome to a group of 150.

This situation creates a lot of problems in the church. Preachers find it very hard to get people to care about more than 150 people. Plus, once those clusters get set up its hard to break into someone's tribe. Humans are naturally cliquey. Churches around 150 can function as one large family. Past 150 the church will have cliques.

Further, as we make calls for social justice it is hard to mobilize congregations to care about people worlds away. The appeals have to be pretty emotional and impactful to get our attention. This is difficult to do on a regular basis. Thus commitment to the poor waxes and wanes.

iii.
What can we do to combat this inclination? Well, here is a humble start. We need to practice what I'll call the rituals of hospitality in everyday life. Most of the people we encounter during the day will be strangers, they will be outside my 150 group. Consequently, I need to cultivate practices of welcome, greeting, kindness, fairness, humility, grace, and openness (among others) to have this interaction be deeply human and humane. I'm probably not going to be best friends with the girl taking my order at McDonald's but I can do everything in my power to treat her as a sister and a friend. I can refuse to dehumanize her. I can look her in the eye. I can smile. I can treat her mistakes with humor and compassion. I can compliment. I can be patient. I can personalize an impersonal interaction.

This is why I think hospitality is so important. It gives us rituals of social interaction that allow us to extend our moral bandwidth to the whole world.