Ever wonder why you can keep up with your family, a few close friends, and some colleagues, but struggle to maintain meaningful relationships with everyone you meet? You might be bumping up against Dunbar’s Number, a fascinating cognitive limit that shapes our social world in profound ways. In this post, we’ll explore what Dunbar’s Number is, why we fall for it, and how understanding it can make us better thinkers, leaders, and learners.

1. What is Dunbar’s Number? #

Dunbar’s Number suggests there’s a cognitive limit to the number of stable social relationships we can realistically maintain – roughly around 150. These aren’t just casual acquaintances you nod to at the grocery store. These are people with whom you have a sense of obligation, shared history, and reciprocal interaction. You’d feel comfortable calling them for a favor, and vice versa.

The psychological roots of this limit lie in the size and complexity of our brains, particularly the neocortex. Robin Dunbar, the British anthropologist who proposed the concept, studied primates and found a correlation between neocortex size and social group size. He extrapolated this to humans, suggesting that our brain’s processing power limits the number of complex social relationships we can manage effectively. It’s all about the cognitive resources needed to track relationships, remember histories, and predict behaviors.

2. Why We Fall For It #

We fall for Dunbar’s Number because our brains are wired for efficiency. Maintaining a strong social network requires constant investment: remembering birthdays, understanding social cues, and resolving conflicts. As our social circles expand, the cognitive load increases exponentially. Dunbar argued that gossip (in its original form, not necessarily malicious) served as a critical function: sharing information about others, solidifying social bonds, and reinforcing group norms. But even gossip has its limits.

Think of it like this: each relationship is like a software program running in your brain. A few programs are fine, but as you load up dozens or hundreds, your system starts to slow down and crash. Our brains are simply not designed to handle an unlimited number of intimate connections. Historical examples, such as the typical size of pre-industrial villages and military companies, often cluster around the 150 mark, suggesting this limit has been operative for a long time.

3. Examples in Real Life #

Dunbar’s Number influences various aspects of our lives:

• Hiring and Team Management: Companies often struggle to scale beyond a certain size without experiencing communication breakdowns and inefficiencies. The principle of smaller, autonomous teams aligns with the idea that individuals can only effectively collaborate within a manageable social circle. Trying to force a larger team to operate as a cohesive unit often leads to frustration and reduced productivity.

• News Consumption: In today’s information-saturated world, we’re bombarded with news and opinions from countless sources. Dunbar’s Number suggests that we tend to gravitate toward a relatively small, trusted group of news outlets and commentators that align with our existing views. This can create echo chambers and limit our exposure to diverse perspectives.

• Health Decisions: We often rely on a small group of trusted friends and family members for advice on important health decisions. While this can be helpful, it can also lead to suboptimal choices if our inner circle lacks diverse expertise or perspectives.

4. Consequences of the Bias #

When we ignore Dunbar’s Number, several negative consequences can arise:

• Distorted Judgment: Over-reliance on a limited social circle can create filter bubbles and confirmation bias, reinforcing existing beliefs and limiting exposure to dissenting opinions.
• Polarized Opinions: As we spend more time within echo chambers, our views become more extreme and less nuanced, leading to increased polarization and social division.
• Undermined Learning: Limiting our exposure to diverse perspectives hinders our ability to learn and grow. We become less open to new ideas and less willing to challenge our own assumptions.

5. How to Recognize and Reduce It #

Spotting and mitigating the influence of Dunbar’s Number requires conscious effort:

• Introspection: Regularly assess your social circle. Are you primarily surrounded by people who share your views? Are you making a conscious effort to engage with diverse perspectives?
• Devil’s Advocate Thinking: Actively seek out viewpoints that challenge your own. Force yourself to consider the merits of opposing arguments.
• Pre-Mortems: Before making important decisions, imagine that the decision has failed spectacularly. What factors led to this failure? This can help you identify potential blind spots in your thinking.
• Seek Out Diversity: Intentionally expose yourself to people from different backgrounds, cultures, and political persuasions. Listen to their perspectives with an open mind.

6. Cognitive Biases That Interact With This One #

Dunbar’s Number often interacts with other cognitive biases, amplifying its effects:

• Confirmation Bias: Our tendency to seek out information that confirms our existing beliefs is amplified by Dunbar’s Number. We tend to surround ourselves with people who agree with us, reinforcing our biases and limiting our exposure to dissenting opinions.
• In-Group Bias: We tend to favor members of our own social group (the “in-group”) over members of other groups (the “out-group”). Dunbar’s Number reinforces this bias by limiting our exposure to diverse perspectives and fostering a sense of loyalty to our inner circle.

7. Conclusion #

Dunbar’s Number is a reminder that our cognitive resources are finite, and our social networks are constrained by the limitations of our brains. While we can’t magically expand our cognitive capacity, we can become more aware of the bias’s influence and take steps to mitigate its negative effects. By consciously seeking out diverse perspectives, challenging our assumptions, and fostering a more inclusive social environment, we can break free from the echo chamber and become better thinkers, learners, and leaders.

So, here’s the challenge: this week, intentionally reach out to someone whose views differ significantly from your own. Engage in a respectful conversation and try to understand their perspective. You might be surprised by what you learn.