With the notable exception of vocal and musical quartets, groups of four tend not to last very long. Two persons in the group are apt to find it more satisfying to relate to each other than to either of the others. If the other two feel left out, they have at least that in common. They may feel a need to counteract the advantage a pair has when acting together, over an individual operating alone. The relationship becomes one of two-pairs rather than an effective group of four members.
In decision-making groups, the tendency to split two against two can lead to frustrating stalemates. Differences can be resolved more easily if the group starts out with three or five, rather than four members.
On the other hand, a group of four can be stable if it depends upon unique contributions from each of its members. In a musical quartet each participant’s part is different and essential. The more experience the musicians have in playing together, the better they can perform. Some such groups stay together for decades.
Stability can also result when there is one leader and three subordinates. A similar but short-lived pattern occurs at cocktail parties: studies of social gatherings find frequent clusters of one person talking and three listening.
On our boat, we have decided that Jordan is our captain. Absent of the availability of outside consultation (mission control, psychologist, other experts), a disagreement that results in a tie (2 vs 2) will always be broken by Jordan. We have also allowed room for mutiny. When Pat, Markus and I disagree with Jordan, he will shut up and follow our lead.