What you're describing are overlays to purely materialistic behavior, aka culture. A true dyed-in-the-wool economist (which I'm not) would say that all behavior can be reduced to expressions of value- I'm altruistic because I'm getting an internal, abstract value from the behavior whereas your friend's "salt the field" mother is seeking to preserve value through scarcity. In your neighbors with a surplus example, individual actor me would say that our behavior would probably depend on our relationship as neighbors. Personally, I'd probably come to you and say "how about we pool our honey and bottle our mead together so we save on operating costs and then not undercut each other?" but then we've created a syndicate, which I'd see as cooperation.