In the Middle Ages, there was a multitude of classifications for people. (All we need to do is review The Canterbury Tales to gain some familiarity with the system.) The medieval order of royalty, aristocracy, landed gentry, peasant, burgher, yeoman, knight, vassal, and many subdivisions created a system of expectations, or expectational structure. If I encounter a member of the landed gentry, for example, there is a horizon of expectations for that person that allows me to make sense of the person’s actions, appearance, etc. My expectations can be confirmed of disappointed to varying degrees.
In other words, I have some sense of where to begin with any social interaction. I’ll know whether I should address the person as My Lord or My Lady or Sir or Your Majesty or no title at all. It’s all about reducing complexity or narrowing the horizon of expectations. Many possible forms of address or interaction are excluded from the start. For instance, unless you are a court jester or designated “fool,” informality, sarcasm, vulgarity, etc., are excluded when interacting with someone of a higher social strata. The excluded forms are still possible but they are not expected. It’s not about what can occur–double contingency still exists–but what is expected to occur.
Social Systems Theory 