How to escape the hell of meetings that fail to produce good outcomes

• There’s an optimal number for every group, evolutionary psychologists argue in a new book

The most fundamental questions for all organisations are about numbers. Is there a point when economies of scale are negated by the costs of bureaucracy and alienation? How many people can you admit to a meeting before it becomes a waste of time? What is the optimum size for a committee? Or a panel? Or a board?

Robin Dunbar is a British psychologist and evolutionary biologist who has been thinking about the question of numbers throughout his career. While studying our nearest biological kin, apes and chimpanzees, he came across the “social brain hypothesis”. What sets primates apart from other mammals are the large, cohesive social groups based on bonded relationships that they inhabit.

Such relationships depend on the ability of animals to figure out how others will behave and how to interact with predicted behaviour. That skill requires considerable computational power — in other words, a big brain. The social brain hypothesis dictates that the size of the group that primates form will be limited by the average size of their brains. For humans, the group size is 148, or 150 for convenience.

Having hit on the magic number, Dunbar noticed that it kept coming up everywhere. Hunter-gatherer communities — the communities in which human beings primarily lived until around 12,000 years ago — tended to consist of about 150 people. The basic unit of modern armies is 150. Oxbridge colleges traditionally had between 100 and 200 members. Hutterite and Amish religious communities split up when they reach 150 and “plant” new colonies.

Most people maintain a close personal network of about 150 “friends and family”. These are the people that they see on a regular basis and would go out of their way to help. Outside that magic number, the ties are much looser and the sense of obligation less telling.

Dunbar then went on to discover various smaller numbers that hold significance in human relationships: five represents the number of close relationships that a person can have; 15 represents the number of people who can be considered best friends; and 50 represents your main social circle, the number of people you would invite to a big garden party or major birthday.

In The Social Brain: The Psychology of Successful Groups, Dunbar has teamed up with Tracey Camilleri and Samantha Rockey, two Oxford University colleagues at the Saïd Business School, to apply his insights to the business world. The authors not only explain the importance of getting the numbers right for various business processes. They also draw lessons from evolutionary biology about how to make sure that groups of various sizes work well together.

The authors emphasise the importance of matching the size of the group to the task at hand — something that ought to be obvious but is ignored with surprising frequency. If you need to make decisions fast, as in crisis management or creative development, five is a good number. (An analysis of 58 software development teams found that the five most successful teams averaged 4.4 members while the five least successful ones averaged 7.8 members. Five also provides a natural tie-break.)

If you want to make complex decisions, then 12 to 15 is a better size, since it provides more perspectives. Work groups can contain six to 12 people, provided that each person knows his or her role and the agenda is clear. Fifty is a good number for an information-sharing meeting if you have a clear leader and a fixed agenda. Fifty is also the maximum number at which it is possible to run a “community of practice” along simple democratic lines without a formal management system.

The cost of ignoring these numerical constraints can be seen everywhere in business. Oversized board meetings fail to provide proper oversight. Oversized crisis management teams bicker while the company burns. Oversized meetings of all kinds allow bores to hold court or else the meetings dissolve into a cacophony of competing voices.

The authors also make much of the dangers of gigantism. Chris Cox, who was chief product officer at Facebook in 2005 when the company had fewer than 100 employees, told a meeting of the Aspen Ideas Festival in 2019 that “I’ve talked to so many start-up CEOs who say that after they pass this number [150 employees] weird stuff starts to happen”.

Patty McCord, a former chief talent officer at Netflix, talks about a “stand-on-the-chair number”: If you stand on a chair and shout and people still can’t hear you, then you know you are in the realm of “weird stuff” starting to happen. You need to rethink how you are organised.

The danger is that companies will be so focused on economies of scale that they lazily add more managers without recognising the costs this exacts in bureaucratisation, alienation and freeriding. Faces disappear into the crowd. Meetings multiply and metastasise. People become functions (“marketing”, “product and development”). “We” becomes “us” and “them”. Intelligent companies work hard to avoid this by breaking themselves into smaller units — that is “growing large by staying small”.

It turns out that several companies instinctively hit on the problems of the “Dunbar number” before Dunbar himself did. When Wilbert (Bill) Gore established WL Gore and

Associates with his wife, Genevieve, in 1958, he limited the size of his plants to 150 because he had seen the costs of alienation when working for a multinational. (The average size of plants is now closer to 250 than 150.) The Mars family was so keen on capping the size of the confectionery company’s headquarters at 50 that one member of the family routinely counted all the punch cards (even the CEO had to punch in until 2008) and raise the alarm if more than 50 were there. (Since the company’s acquisition of Wrigley in 2008, the size of the global HQ has been raised to 100.)

The authors also suggest that companies should use the insights of evolutionary biology to build and reinforce the social bonds that make companies function well.

The great feasts of Oxford colleges and City guilds are not acts of self-indulgence, as they might appear, but highly effective bonding rituals that ease the flow of ideas and commerce. The post-Covid fashion for working from home means that companies will have to redouble bonding efforts.

Our authors are rather too keen on repeating the same points over and over rather than exploring possible objections. The human scale imposes costs as well as benefits. Anthony Trollope wrote immortal novels about the feuds that split asunder the small clerical world of Barchester. Oxbridge colleges are notorious for the internecine quarrels which can have bigbrained intellectuals behaving like squabbling children.

Family companies suffer from more value-destroying feuds than public companies because they mix family tensions with pecuniary gain, as viewers of the hit series Succession know all too well.

Small institutions also have the habit of becoming nests of sybarites unless they are subjected to external discipline. Edward Gibbon complained that he learnt nothing at Oxford because the tutors at his college, Magdalen (which also happens to be Dunbar’s college), were “sunk in port and prejudice” and almost completely indifferent to education.

The university became a centre of excellence only when 19th-century reformers forced it to select its fellows based on open competition rather than “founders’ kin” and personal connections. Sensible family companies bring in external managers to add not just professionalism but perspective. Sometimes you must fight against natural instincts such as nepotism to bring out the best in human potential.

Our authors are particularly frustrating on the question of diversity. They point out that human beings have a natural tendency towards homophily — they naturally seek out those who share their interests and experiences. Homophily efficiently deals with organisational gremlins such as building trust and promoting mutual understanding — hence the success of institutions that have traditionally drawn their members from a narrow range of backgrounds.

But they also blandly endorse the vogue for diversity. They may well be right that the value of diversity in bringing different perspectives is dispositive — that the juice is more than worth the squeeze, to borrow a phrase, as it was when the inbred Oxford colleges that Gibbon condemned were forced to introduce open competition. But it’s negligent at best and cowardly at worst to praise both homophily and diversity without examining the tension between the two.

This habit of dodging difficult questions is annoying because The Social Brain is otherwise intellectually brave. Management science has always had a weakness for what the English literature don (and misfit) FR Leavis called the “technologico-Benthamite reduction of human experience to the quantifiable, the measurable, the manageable”.

Management theorists assume that the best way to motivate people is the carrot and stick. This was the basis of Frederick Taylor’s theory of scientific management in the early 20th century and formed the basis of shareholder maximisation theory more recently. Attempts to embrace “scientific management” with more humanistic management have failed because humanistic management rapidly degenerates into kumbayasinging twaddle.

But evidence is mounting that carrot-and-stick management is poor at promoting long-term loyalty because it fails to reckon with things such as people’s pursuit of meaning and belonging. The Social Brain represents an interesting attempt to factor in the importance of meaning and belonging without indulging in twaddle.

The authors argue that it is perverse for people who are concerned with managing and motivating individuals not to take advantage of what evolutionary biologists have discovered about “what is unchanging in the ways human beings behave ”— as if humans are blank slates to be written on at will rather than particularly intelligent members of the mammal family.

The Social Brain makes a good start in outlining some of the valuable lessons managers can learn from biology. Many more lessons will come as management theorists, exhausted by both the failure of techno-Benthamism and the vacuity of its humanistic alternatives, start to reckon with the explosion of knowledge in the biological sciences.

IF YOU NEED TO MAKE DECISIONS FAST, AS IN CRISIS MANAGEMENT OR CREATIVE DEVELOPMENT, FIVE IS A GOOD NUMBER