April 2, 2024 • 1hr 2min

Robin Dunbar - Optimizing Human Connection (Dunbar's Number) - [Invest Like the Best, EP.367]

Invest Like the Best with Patrick O'Shaughnessy

In this episode, Patrick O'Shaughnessy interviews Robin Dunbar, a renowned biological anthropologist and evolutionary psychologist. Dunbar is best known for proposing Dunbar's number - the cognitive limit to the number of stable relationships humans can maintain. The conversation explores Dunbar's research on social networks, relationship dynamics, and the evolutionary basis for human social behavior.

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Key Takeaways

Dunbar's Number refers to the cognitive limit of about 150 stable relationships humans can maintain
Our social networks are structured in layers, with closer relationships requiring more frequent contact:
- 1.5 - Closest relationships (romantic partner, best friend)
- 5 - "Shoulders to cry on" friends
- 15 - Sympathy group
- 50 - Good friends
- 150 - Meaningful relationships
- 500 - Acquaintances
- 1500 - People you can put names to faces
Face-to-face interaction and physical touch are crucial for building and maintaining close relationships
Homophily - We tend to bond with people similar to us across 7 key dimensions like language, interests, values, etc.
Social bonding activities like laughter, singing, dancing, and storytelling trigger endorphin release and strengthen relationships
Time is the fundamental limiting factor in maintaining relationships and social networks
Providing opportunities for social bonding at work (e.g. choirs, social clubs) can improve employee wellbeing and productivity
Technology and social media are poor substitutes for in-person interaction in building meaningful relationships

Introduction

In this episode, Patrick O'Shaughnessy interviews Robin Dunbar, a renowned biological anthropologist and evolutionary psychologist. Dunbar is best known for proposing Dunbar's number - the cognitive limit to the number of stable relationships humans can maintain. The conversation explores Dunbar's research on social networks, relationship dynamics, and the evolutionary basis for human social behavior.

Topics Discussed

The Origins of Dunbar's Number (2:47)

Dunbar explains how he arrived at the famous "Dunbar's number" of about 150 stable relationships:

It began with studying primate brain sizes and social group sizes
He found a correlation between brain size and group size in primates
Extrapolating to human brain size predicted a group size of about 150
This matched observed sizes of hunter-gatherer clans and other natural human groupings

As Dunbar states: "We just kept finding this number everywhere we looked in the modern world, our entire modern world is built around this number, 150."

Layers of Human Social Networks (5:45)

Dunbar describes how our social networks are structured in layers:

1.5 layer - Closest relationships (romantic partner, best friend)
5 layer - "Shoulders to cry on" friends
15 layer - Sympathy group
50 layer - Good friends
150 layer - Meaningful relationships
500 layer - Acquaintances
1500 layer - People you can put names to faces

Each layer requires a certain frequency of contact to maintain relationships. For example, the 5 layer requires weekly contact, while the 15 layer requires monthly contact.

The Importance of the 1.5 Layer (10:30)

Dunbar explains the significance of the 1.5 layer:

Represents our closest relationships - romantic partner and/or best friend
85% of women have a platonic "best friend forever" in addition to romantic partner
Men tend to have either a romantic partner OR a best friend in this layer

"Women have a platonic friend called a best friend forever. BFF. And that's nearly always another woman. Not 100%, 85% of women at any one time have a best friend forever."

Surprising Research Findings (15:10)

Dunbar shares some of the most surprising findings from his research:

A Facebook study of 61 million users found an average of 149 friends
Brain region sizes correlate with social network size
The layered structure of social networks is seen in other primates as well
The specific numbers (5, 15, 50, 150) represent optimal points for information flow in networks

Implications for Organizational Structure (21:09)

Dunbar discusses how his research applies to structuring businesses and organizations:

Small teams of 5-6 people with similar backgrounds work most efficiently on focused tasks
Larger, more diverse groups of ~15 are better for brainstorming
Boards and committees should aim for 15-50 members
Very large groups (150+) become inefficient as many members disengage

"If you got a task, develop a bit of code for some computer program, or figure out some processes...it's best to have a very small group. They will work much faster and much more efficiently, but they need to know each other in the sense that they all come from the same background."

The Science of Social Bonding (28:18)

Dunbar explains the biological mechanisms behind social bonding:

Physical touch, especially grooming, triggers endorphin release in primates
Humans have evolved additional bonding activities that don't require touch:
- Laughter
- Singing
- Dancing
- Storytelling
- Eating together
- Religious rituals
These activities trigger endorphin release and increase sense of social bonding

"We found lots of ways that allow us to trigger the endorphin system directly without involving physical touch. And these are in order with which they appeared in the course of human evolution, we think laughter, singing, dancing."

Limitations of Digital Interactions (34:16)

Dunbar discusses why digital communication is a poor substitute for in-person interaction:

Lacks the endorphin-triggering effects of physical presence
Can maintain existing relationships but struggles to build new deep connections
Missing important non-verbal cues for building trust

"If you don't meet up once in a while, face to face, nothing on earth or Facebook is going to stop that friendship gradually becoming an acquaintanceship."

Reviving Social Bonding at Work (36:16)

Dunbar advocates for bringing back social activities in the workplace:

Victorian-era companies built social clubs, sports facilities for employees
Modern examples like Facebook's weekly beer and barbecue events
Simple activities like forming a company choir can dramatically improve morale

"I think in our haste to find efficiencies, we've forgotten the lessons actually of the founders, the entrepreneurs who founded the big multinationals of today, back in Victorian Edwardian times, 150 years ago, because they all recognized that a bonded workforce, happy workforce was highly beneficial in terms of productivity."

The Concept of Homophily (42:40)

Dunbar explains homophily - our tendency to bond with similar people:

We tend to befriend people similar to us across 7 key dimensions:
- Language
- Where you grew up
- Career trajectory
- Hobbies and interests
- Moral, political and religious views
- Musical taste
- Sense of humor
Also applies to fixed traits like gender, age, personality type
Reduces friction in relationships but can lead to "echo chambers"

"The more of these boxes you tick with somebody, the closer in they will be in your inner circles and the more intense and the longer those relationships will last."

Challenges of Loneliness and Building Trust (52:21)

Dunbar discusses the growing problem of loneliness and challenges in building trust:

Young people struggle to build social networks after leaving structured environments like school
Close local friendships are crucial for mental and physical health
Organizations need to provide opportunities for organic friendship formation
Online interactions make it harder to evaluate trustworthiness

"Trust is what creates and maintains our relationships with each other. And when things fall apart, it's always because trust is broken down."

Impact of Technology, Religion, and Mental Health (52:21)

Dunbar reflects on major societal trends affecting social connections:

Technology - Poor substitute for in-person interaction, can lead to "avatar" relationships
Decline of religion - Loss of community-building rituals and activities
Mental health issues - Linked to lack of close social connections

"The best predictor of your mental health and wellbeing and your physical health and wellbeing is the number of close friends you have. And those close friends need to be there. It's no good having them at the end of a telephone line or a computer screen."

Time as a Fundamental Aspect of Social Dynamics (59:45)

Dunbar emphasizes the importance of time in social relationships:

Time is the fundamental limiting factor in maintaining relationships
We have to allocate our limited time across our social network
Many human behaviors and innovations are attempts to overcome time constraints

"We don't have infinite time. A lot of things we do are attempts to cut through time constraints."

Conclusion

Robin Dunbar's research provides profound insights into the nature of human social networks and relationships. His work highlights the importance of face-to-face interaction, the layered structure of our social circles, and the biological mechanisms underlying social bonding. As society grapples with issues of loneliness, digital communication, and changing social structures, Dunbar's findings offer valuable guidance for building stronger, more fulfilling relationships and communities.