Conversational Group Limit
Dunbar, who created the Dunbar's Number, says that language is a 'cheap' form of social grooming(akin to flea picking in apes). Its more efficient - you can talk to more than one person at a time - and you can do it when doing other things.
But its not freely salable.
"Human conversation group sizes should be limited to about 3.8 in size (one speaker plus 2.8 listeners)."
Conversation can go up to 5 people - but rarely does it go beyond that. If there is more than 5 people, it generally splits into smaller groups.