This paper argues that in all areas of communication theory, we should give greater consideration to the possibility of expression affecting the expresser. A general model of the effects of messages on both senders and receivers is introduced, organizing and resolving contradictions in past research by distinguishing between effects of the expectation of expression, effects of message composition, and effects of a message being released to others. When applied to deliberation, the model results in several experimentally testable explanations of causal mechanisms involved in deliberation’s predicted effects, a stronger basis for the distinction between deliberative and argumentative discussion, and several tentative practical recommendations for encouraging open-mindedness in deliberation. doi:10.1111/j.1468-2885.2007.00306.x When both scholars and laypeople attempt to explain communication, they most often do so using a reception-effects paradigm in which all effects of communication are assumed to result from message reception. Communication is thought of in terms of several related metaphors, such as information flow and information transmission (Krippendorff, 1993), all of which imply that preexisting information travels in some form from one actor to another and then has its effects, if any, on arrival. This paradigm guides our thinking away from several possibilities, including that the act of expression might change the message sender, that expressed ideas often do not exist intact, if at all, in the sender’s mind prior to expression, and that attention to— and thus effects of—received messages may result from the expectation of being able to respond. This paper offers a general model of the effects of both sending and receiving messages, organizes the disconnected but substantial empirical evidence for its expression-effects propositions, and illustrates the model’s utility by using it to generate alternative explanations of some of the predicted effects of deliberation.