Shevy presented early versions of this model in his dissertation, at ICMPC (Montreal), SCSMI (Copenhagen), and AEJMC (Denver). He has continued to refine it since then. It identifies six main categories of antecedents - things that cause, influence, or sustain - any media effect. They are...
1. User characteristics. All media effects have their origin within the user - the person creating and receiving media messages or otherwise using media.) Characteristics include variables such as demographics, psychographics, personality, knowledge, attitudes, need for cognition, cognitive ability, mood, emotion, physical ability, etc.
2. Context. Media effects do not occur within a void. There are various types of contexts, such as cultural, social, environmental, etc.
3. Media Content. The messages, arguments, images. It is inseparable from form.
4. Media Form. How the content is presented. There seems to be at least three dimensions of form: 1) Sensory/Perceptual - how loud the sound is, how bright the colors are, how fast objects move toward the camera. Editing pace. Pace of the story. (To what extent is pace perceptual in terms of creating effects such as attraction, aversion, comfort, and discomfort vs. merely an effect of cognitive load, which may not be as rooted in sensory perception? 2)Narrative form. This is how the story is told. It might include style, chronological order, and placement of edits (how much of a shot is shown, when the storyline or perspective changes direction, etc., as opposed to the mere pace of edits.) 3) Interactivity. How much (quantitative) and in what ways (qualitative) the technology allows users to control the content, form, and nature of the discourse.
5. Interaction. The confluence of user characteristics and technology (form in terms of interactivity) resulting in the actual amount of interaction occurring during media exposure. Interaction alters content, form, and user characteristics (e.g., limited cognitive resources devoted to interaction may lower cognitive ability for some message processing.) The mere presence of interactive features in a medium does not mean that interaction is occurring at a particular point in time. Users watch movies with low interaction on computers and gaming consoles (high interactivity). Video games have periods of higher interaction (playing time) and periods of lower interaction (cut scenes).
6. Time. The formation of effects occurs over time. The existence of the effect is only for a period of time. Time may be considered in short periods of milliseconds or longer periods of months and years. It can be cyclical - a sad person (user characteristic) begins to watch a funny movie (content & form), and after the first scene, the person's mood lightens a bit (an effect that has altered the user characteristics). Now, repeat the process, going into the second scene... the user, in a better mood (user characteristic), sees the second scene (content & form), and laughs until it hurts (an effect of pain), which alters the user characteristics going into the third scene. This could be considered as a linear process as well as cyclical, and the time segments could be based on something shorter or longer than scenes. The point is that there are multiple ways to consider the timing of media effects processes, and choosing the appropriate time frame is important to observing and understanding media effects. Choosing incorrectly could result in missing the effect altogether, even if an effect really did occur.