I think the size of the hunting band is the core question. There
is something about 6 being to little and 16 being too much. While
Dunbar's number is the low bar for information, there is something
optimal about a group that is close to ten in number. I think
it might be something to do with personality types or traits.
You need enought people to keep the interaction energized and
not stuck in little alliances, but you can't have so many people
that you can't remember how to predict them to a degree.
1 + 1 = One is always dominant
1 + 1 + 1 = Shifting compromises
2 + 2 = Opposing gangs, stalemate
2 + 3 = Majority rule
2 + 2 + 1 = Stalemate and a judge
3 + 3 and forward = The likelihood of gangs having only two sides
becomes lower. The combinations would result
in more vibrant discussions than with the
lower levels. Stagnation lessens.