What Is the Right Size for a Group Conversation?

Why do our conversations usually involve no more than four people?

Posted Jul 18, 2017

Ivanko80/Shutterstock
Source: Ivanko80/Shutterstock

Conversations are funny things.

If you have ever attended a large gathering of old friends and relatives whom you have not seen for a while, you may have gone home disappointed that you only got to speak to some of the individuals you had hoped to reconnect with. Similarly, you have probably noticed that when the gang from the office goes out for drinks after work on Friday afternoon, the crowd invariably splits up into smaller conversations.

Is there a natural limit to the size of the group that can sustain a meaningful conversation? Recent studies conducted by Jamie Krems and Steve Neuberg of Arizona State University and Robin Dunbar of Oxford University suggest that this may in fact be the case.

In their first study, they approached groups of two or more students engaged in conversations in public areas of a university campus. They asked the conversationalists to report what they had been talking about just before the researcher interrupted them. They found that there were rarely more than four people involved in a conversation at any one time, but this was perhaps even more interesting: They also found that if people were gossiping about another person who was not present, the size of the group averaged about one fewer person in size than if the group was discussing some other sort of topic.

In a second study, they analyzed the conversations in 10 different plays by William Shakespeare. Scholars have long been aware that conversational patterns in Shakespearean plays accurately reflect the dynamics of real-life social interactions — which is one reason their appeal has endured over time. If this is the case, it would be interesting to find out if Shakespeare applied the “maximum size of a conversation” rule to the characters in his plays. Krems and her colleagues discovered that no conversation in any play they analyzed ever involved more than five characters, and they replicated the effect that scenes in which characters were discussing absent others had on average one fewer individual involved.

So, what is so special about the number four (plus or minus one) when it comes to conversations?

Krems, Dunbar, and Neuberg propose that the size of our conversations is restricted by our “mentalizing constraints,” or the limits on the cognitive demands that we can handle in our interactions with others.

This is all related to what psychologists call our “Theory of Mind,” or the ability to understand that other people do not necessarily know or intend the same things that we ourselves do. Having a functioning theory of mind is essential for successfully managing one's social life. If two people are engaged in conversation, each must understand what his or her partner intends and what each person understands about the other’s state of mind.

This gets more complicated as you add people to a conversation. If you have three people (or stooges) in a conversation, Moe must understand not only what Larry understands about Moe and what Curly understands about Moe, but also what Larry and Curly understand about each other. Add a fourth or fifth person to the mix, and you have increased the complexity enormously. Thus, it appears that when you move beyond four or five people, a conversation simply gets too mentally taxing for most people to sustain a prolonged conversation.

And there is a reason why talking about an absent person makes things even more difficult. In this type of talk, you must also be able to reflect on the understanding, intentions, and feelings of the absent person, which cuts back on the number of people we can manage in real time during the conversation. The data analyses in the two studies I have described indicated that this explanation was more plausible than other possible explanations for this phenomenon.

Certainly, other situational factors, such as the arrangement of furniture, can influence the ease of conversations. For example, although side-by-side seating connotes intimacy, it does not seem to be the preferred arrangement for talking.  Studies have shown that side-by-side seating on a couch inhibits conversation in otherwise sociable people, and individuals only choose a side-by-side position for conversation when it was not possible to arrange a face-to-face conversation at a distance of less than five-and-a-half feet.

In other words, if it is good conversation that you are after at a party, stay away from the couches.

The fascinating finding that our mentalizing capacity limits the size of our conversations has many implications: If individuals differ from each other in mentalizing capacity, it is possible that having the ability to juggle larger conversation sizes is one component of having good social skills — something with an obvious payoff. Krems and her colleagues also suggest that reading fiction may help us to expand our mentalizing capacity by exercising the ability to follow conversations in literature.

A silver lining for English majors after all?

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