What is Dunbar’s Number and How it Affects your Startup?

Why 150 Changes Everything For Your Startup

Alexander Lim
6 min readMar 28, 2021

Dunbar’s Number is a proposed cognitive limit to the number of people with whom one can maintain stable social relationships.

The number was first proposed in the ’90s by anthropologist Robin Dunbar.

It is a number that is widely accepted as accurate but holds some controversy in the field of anthropology.

Like any academic theory, it gets challenged here and there, but it has held firm for nearly 25 years without ever being disproved.

Dunbar’s Number: 150

The most widely accepted value of Dunbar’s Number is 150. This means that we can only keep track of and maintain stable relationships with 150 people at any given time.

To understand why this number occurs, we need to look at how our brains process information differently than computers do.

Computers organize information into neat little files and folders so they can store and access it more easily.

Our brains don’t work that way because they aren’t computers; they are biological organs designed to think critically about our world and interact with it as intelligently as possible over time.

Our brains are much more fluid when it comes to storing information because they do this in our long-term memory, not a physical location in our brains like a hard drive or even a flash drive, but more of a functional location.

Long-term memory is the part of our brains that allows us to learn new things and quickly adapt to new environments.

This is where we store information about people, like their faces, mannerisms, and voices. We also store information about places like their layout, smells, and sounds.

Furthermore, we store information about events that have happened in our lives, such as great moments (weddings, graduations, etc.) or traumatic experiences (deaths, illnesses, etc.).

These different information pieces are stored in long-term memory and connected through various interactions we have had with those people/places/things over time.

This is why it’s hard for us to forget certain events and why some memories stand out more than others.

Our brains connect these dots between these memories through what is called an associative network.

Associative networks are built from repeated interactions; therefore, there are patterns in how they are built and structured across time.

Associative networks tell us information about a person we know by helping us remember that person’s face or where they were born.

They tell us when they were born by connecting these pieces of information through repeated interactions over time. They help us remember how we know them through repeated interactions over time.

Our associative networks are extremely complex and only get more complex as people are added to our network. But these networks work in a specific way, and we can learn from them to determine Dunbar’s number.

The Structure of an Associative Network:

Social networks are structured similarly to our associative networks, but they have a few key differences that can help us understand why Dunbar’s Number is 150 and how it affects startups:

1. The more connections a social network has, the larger it is (think Facebook and Twitter)

2. There are many different types of connections in a social network (think friends, family, co-workers, etc.)

3. Each connection is different from the other (think one friend will advise on your career/business when another friend will advise on your relationship/family).

The structure of social networks doesn’t differ much from our associative networks’ structure because they were heavily influenced by each other over time as humans evolved and became social creatures.

The internet was created as a social tool and has become a major influencer in how we interact with each other.

Our brains are constantly adapting to this, and so is our associative network, which social networks have influenced over time.

This is why our associative networks store information about people we know on Facebook, Twitter, Linkedin, etc.

The more we use these tools to connect with people, the more we will associate them with that site and others like it.

Social Networks Make Dunbar’s Number Limit Smaller:

Dunbar’s Number is 150, but it doesn’t have to be 150 if you use certain tools like social networks.

This is because social networks give us an advantage in keeping track of relationships with more people.

They do this by eliminating a lot of the work that our brains would normally have to do to keep track of everyone we know; they do this through repeated interactions over time stored in our long-term memory.

Our brains don’t need to work extra hard to store these pieces of information because they are being stored online for us through repeated interactions over time using social networks such as Twitter and Facebook.

This allows us to keep track of hundreds or even thousands of people without putting much work into it.

The more connections you have with people online, the easier it is to keep track of them. Social networks make Dunbar’s Number smaller because they store information about people for you in a way that is easily accessible.

They store information about their face, mannerisms, and voice so that you don’t have to.

If you were to meet someone at a conference and want to remember who they are, then your brain will already know most of the information because you have seen pictures and videos of them on social networks like Twitter, Facebook, or Linkedin.

Social networks make Dunbar’s Number smaller because they act as an extension of our associative network.

This helps us keep track of more people while using less mental energy and making fewer mistakes.

This is why social networks are critical for startups and how they grow over time; the more people who use your startup, the bigger your network will be, and the easier it will be for your startup to grow exponentially over time.

Using Dunbar’s Number to Manage Your Employees:

The effect of Dunbar’s number on your startup is simple: you will be able to build an effective team. The most effective teams are comprised of no more than 15 people.

When you have a team of fewer than 15 people, it is easier to communicate and help each other with daily tasks.

Why? Because, even though the crew may be big enough, each person in your team will still feel like he or she has a significant role. This will lead to better communication and collaboration.

In a team of more than 15 people, this feeling disappears quickly as each group member loses sight of their own value. Communication becomes harder, and collaboration suffers as well.

Teams that are too big are less productive because of the communication gaps between group members.

It’s hard to communicate what you’re doing when there are more than 10 people in the same room, let alone talk about what needs to be done by tomorrow’s meeting!

And if everyone talks at once… good luck trying to know what is happening.

You can see the same effect in the animal kingdom: if you look at the wolf pack structure, you’ll see that their number is usually between 6 and 10 animals.

This means that the wolf pack is big enough for hunting but small enough for each group member to feel important.

If the wolf pack were bigger, it would be impossible for everyone to know each other and take care of each other.

That’s why there are only 6–10 wolves in a pack!

When you build your startup team, ask yourself, “What is Dunbar’s Number?”. If your company has more than 10 employees, it may be time to reorganize or hire new team members.

Remember that the more you grow, the harder it becomes to be productive.

About the Author

I am the Founder of Cudy Technologies (www.cudy.co), a full-stack EdTech startup helping teachers and students learn better. I am also a mentor and angel investor in other Startups of my other interests (Proptech, Fintech, HRtech, Ride-hailing, C2C marketplaces, and SaaS). You can also find me on Cudy for early-stage Startup Founder mentorship and advice.

You can connect with me on Linkedin (https://www.linkedin.com/in/alexanderlhk) and let me know that you are a reader of my Medium posts in your invitation message.

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Alexander Lim
Alexander Lim

Written by Alexander Lim

Founder of Cudy Technologies (www.cudy.co), a full-stack EdTech startup helping teachers and students teach and learn better. I am also a mentor and investor.

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