I’m not sure that “group average” is always the metric we want to improve. My intuition is that we want to think of most groups as markets, and supply and demand for various types of interaction with particular people varies from day to day. Adding more people to the market, even if they’re below average, can easily create surplus to the benefit of all and be desirable.
Obviously even in real markets it’s not always beneficial to have more entrants, I think mainly because of coordination costs as the market grows. So in my model, adding extra members to the group is typically good as long as they can pay for their own coordination costs in terms of the value they provide to the group.
I’m not sure that “group average” is always the metric we want to improve. My intuition is that we want to think of most groups as markets, and supply and demand for various types of interaction with particular people varies from day to day. Adding more people to the market, even if they’re below average, can easily create surplus to the benefit of all and be desirable.
Obviously even in real markets it’s not always beneficial to have more entrants, I think mainly because of coordination costs as the market grows. So in my model, adding extra members to the group is typically good as long as they can pay for their own coordination costs in terms of the value they provide to the group.