How on Earth Do People Understand Each Other in Everyday Conversation?

These examples demonstrate how complicated it is for listeners to understand what someone means to say, and, accordingly, how complex it is for a speaker to convey a simple message to someone. In order to understand, and to be understood, conversation partners must take the context and each other's viewpoint into account. Research has shown that perspective taking and determining  common ground are crucial here.

Perspective taking and common ground

Perspective taking is one of the most important requirements for successful communication (Holtgraves, 2002Krauss & Fussell, 1991). To get a message across a speaker must consider whether a conversation partner can understand what (s)he is saying. At the same time, a listener must consider the perspective of the speaker to understand the intention behind an utterance (what could he or she mean given his perspective?). Suppose your friend asks you "Isn't she from New York?". Before you can reply to this question you must understand who your friend is referring to. If you were in the middle of a conversation about the author of a book, you probably think he is referring to the author. However, maybe your friend strayed off and is referring to the singer of a song he hears on the radio. The question would be unclear to you if you were unaware of this sudden change in topic. To prevent miscommunication your friend would have to consider your perspective and indicate the change of topic by saying "This singer, isn't she from New York?", otherwise you may quite likely assume he is still talking about the author of the book (from Moskowitz, 2005).

Thus, to maintain mutual understanding conversation partners need to take each other's perspective. Yet, how does this work? An important area of research has revealed that conversation partners do this by constantly trying to determine what is common ground (Clark, 1996). Common ground refers to the knowledge that conversation partners share; the information conversation partners (have come to) mutually know, believe, and recognize. It has been shown that people rely on  heuristics, or rules of thumb, that allow them to asses what is part of common ground (Clark & Brennan, 1991).

One of these rules of thumb that people rely on is the heuristic of physical copresence. If two people are physically together and attending to roughly the same aspect of their environment, they assume that what both perceive is common ground. When someone is passing by in front of you, you can assume that the person's behaviour and appearance is mutually known, and you consequently don't need to describe this to your conversation partner.
A second rule of thumb is the so-called heuristic of linguistic copresence. This means that people generally assume that information previously introduced during a conversation is part of the common ground. This simply means that once you have mentioned something, you don't need to explain it again. 

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