Journal · Short film
Your business has a Dunbar's number too
The famous limit of about 150 relationships is disputed. The idea underneath it explains when a small business runs out of memory.
Captions are on. The described version stops at each scene while a voice says what's on screen; that voice is synthetic, and the narration is ours. There's no sign-language version yet. The full transcript is below.
The number
In the 1990s, the anthropologist Robin Dunbar compared brain size and group size across primates. From that relationship he predicted humans can keep track of about 150 stable relationships.
The dispute
It's a famous number, and a heavily disputed one. A 2021 reanalysis using newer data and methods found the estimate can't be pinned down: the plausible range for humans was too wide to give one figure at all.
The idea underneath holds up better: a group can only keep so much in its own head before it runs out of space.
The business version
Your business has a limit like that. It isn't a headcount. It's the point where the knowledge stops fitting: which customer pays late, where the spare parts are, what the usual order looks like.
When that lives in three people's heads, it works until one of them goes on vacation or is off sick. That's when businesses start shopping for an ERP. Not because they got big, but because they ran out of memory.
An ERP like ERPNext is shared memory: the usual order is written down so anyone can find it when it's needed. That matters for AI too. An AI can read your records. It can't read what's in someone's head while they're on a beach.
What this doesn't prove
That there's a magic size. Some 10-person firms need an ERP. Some 50-person firms are organised well enough that they don't.
Count what lives only in someone's head.
Transcript
Narration as spoken, with what's on screen described in the indented lines. Company names and amounts in the film are made up.
On screen: 150 gold dots drop into a grid while a counter climbs to 150. About 150 relationships.
Dunbar's number, about 150. In the 1990s, the anthropologist Robin Dunbar compared brain size and group size across primates.
On screen: 150 gold dots drop into a grid while a counter climbs to 150. About 150 relationships.
He predicted humans can keep track of about 150 stable relationships. Who's who? Who owes whom? Who isn't speaking to who? It's a famous number. It's also heavily disputed. A 2021 reanalysis found the data can't pin down one figure at all, but the idea underneath holds up. A group can only keep so much in its own head before it runs out of space. Your business has a limit like that. It's not a head count. It's the point where the knowledge stops fitting. Which customer pays late? Where the spare parts are? What usually does this order look like?
On screen: Three heads, each holding a few gold dots of knowledge. One slides away on vacation and its dots fall.
When it lives in three people's heads, it works until one of them goes on vacation or someone's not feeling well and didn't come into work today. That's when businesses start shopping for an ERP. Not because they got big, but because they ran out of memory and they need higher quality of customer care. An ERP like ERPNext is shared memory. It's where the understanding of what the usual order gets is written down so that anyone can find it at the moment it's needed. And it matters most of all for AI. An AI can read your records. It can't read what's in Dave's head when he's on vacation sipping a Mai Tai on the beach.
On screen: Card: What this doesn't prove. That there's a magic size. Count what lives only in someone's head.
There's no magic size for this. Some 10-person firms need it. Some 50-person firms are streamlined to the point that they don't. Count what lives only in someone's head if it helps your team grow.
On screen: End card: the Highland Willow willow-tree logo grows from its trunk and roots into its canopy, then the words Highland Willow, highlandwillow.com/journal, and We publish our working.
Sources
- Dunbar, R. I. M. (1992). "Neocortex size as a constraint on group size in primates." Journal of Human Evolution 22(6).
- Lindenfors, P., Wartel, A. and Lind, J. (2021). "'Dunbar's number' deconstructed." Biology Letters 17(5), 20210158.
Narrated and produced by Highland Willow. The audio-description voice is synthetic (macOS text-to-speech). The animation is drawn in code. None of the film's data comes from any client.