1. A method for modifying computer mediated communications, the method comprising: at a computer system including one or more processors and memory: receiving input video data from a digital camera, the input video data including a first segment of the input video data corresponding to recorded non-verbal behavior of a first participant in a computer mediated communication; generating a first portion of an output stream of video data, wherein generating the first portion of the output stream of video data includes: comparing the recorded non-verbal behavior to a predefined behavioral model, wherein the behavioral model defines behavioral parameters; and in accordance with a determination that the recorded non-verbal behavior is inconsistent with the behavioral model, determining alternative behavior that is consistent with the behavioral model; and including the alternative behavior in the first portion of the output stream of video data in place of behavior representative of the recorded non-verbal behavior in the respective video segment; and transmitting the output stream of video data to a second participant in the computer mediated communication.