Affect Control Theory
Here's the essence of ACT, pure and simple. People try to conduct themselves so their feelings are appropriate to the situation, and if their actions aren't working to do this then they change their views of the situation.
Emotions signal how well events are maintaining our definitions of situations. No emotion is felt when interaction maintains a situational identity in character but to only middling degree - e.g., when a Lover feels fairly good, fairly potent, fairly lively. Emotions are felt either when interactions violate the character of an identity (e.g., a Lover ends up feeling bad, weak, and lively - "panic-stricken") or when interactions confirm an identity both in character and degree (e.g., the Lover feels extremely good, extremely potent, extremely alive - "happy, passionate").
While the capacity for emotional experience is the same for everyone, the way affect attaches to specific objects and behaviors varies across people, and different people may be led to different behaviors, emotions, and interpretations because their affective correlations differ. At the same time, those who share affective linkages share many expectations and judgments about social relations without even having to discuss the matters.
What instincts do for animals, affect does for humans, guiding conduct in directions that are familiar and valuable within a social group. Of course, affective associations are totally learned so human "instincts" adapt to changing conditions, and different groups with their different values provide distinctive patterns of conduct. Moreover, affect governs action within the context of environmental constraint and individual intelligence, so cognition and reason always are a factor in behavior.
What happens when you go in a place? For one thing, you have to figure out who you are. You may not think about it much. Usually you define the situation and your place in it fast and unconsciously. But you can see what's happening when things mess up. Have you ever walked into a room expecting one group of people - like coworkers - and found someone else instead - like your sweetheart? When it happens you can feel yourself dropping the readiness for some actions and preparing yourself to act in other ways. You're changing who you are in the sense of changing from one role to another, from one social identity to another.
Obviously, another thing you have to do is figure out who the other people are. That may be simply a matter of recognizing people in uniform like a busdriver, or those who always have the same role with you like your car mechanic, or it may be more complicated like figuring out whether another person is being sweetheart or coworker right now when he or she can be both at different times. Who you are depends on who others are, and what roles others take depends on the role you have, so you have to figure these things out simultaneously.
The solution to the puzzle of defining everyone may require more information, like knowing where you are. You and a coworker aren't supposed to act like sweethearts at the place you work; and it's strange to act like coworkers when you and your sweetheart are alone in a cozy romantic restaurant.
You've defined the situation when you can name the setting and the social identities that everyone has. Ordinarily you don't say the names out loud, but you could if someone asked you to describe where you are and who you are and who are the people with you. Interact does ask! That's the way you define a situation in a simulation.
Each identity that you or others take gives a certain feeling because you have a certain attitude about it. Doctor, for example: unless you have a different attitude than most Americans, you think doctors generally are good and helpful, deep and powerful, quiet and meditative. That's your sentiment about doctors, the way you feel in general about them even though you might have different feelings in some circumstances. The general sentiment about Children is quite different: children (for most Americans) are good, but they're small and weak, and noisy and lively. Gangsters provoke still a different sentiment: bad, powerful, and active.
Sentiments have three different components or aspects: we can feel that something is good or bad, that it is powerful or powerless, and that it is lively or quiet. Each of these aspects is a matter of degree, can be greater or less. For example, some things are slightly good, others are quite good, still others are extremely good.
One way of picturing this is to imagine that sentiments are floating around the room you're in. Those things that are very good are up near the ceiling, those that are very bad are near the floor. Things that are powerful are near the wall in front of you, weak things are near the wall behind you. Lively things are on your right, and quiet things are on the left side. Things that don't strike you as either good or bad, powerful or powerless, lively or quiet hang right around the center of the room. So to "see" a Doctor you glance upward to your left; to see a Gangster you look down to your right; and to see a Child you turn your head and look up over your right shoulder.
You have sentiments about ways of acting, too. Look up in front of you to your right, and there's Cheering someone on. Now drop your eyes to the floor along that same corner of the room, and you see Socking someone. Look down behind you on the left; there's Ignoring someone. Look up, forward to your left to see Soothing someone. Each behavior has a sentiment attached to it that reflects how good it is, how powerful, how lively.
The short names for the three aspects of sentiments are Evaluation, Potency, and Activity, and sometimes these are abbreviated further with the initials EPA. We represent a sentiment precisely by measuring it on the three aspects. The custom is to measure everything from the center of the room and use plus units to measure up (goodness), forward (powerfulness), and right (liveliness); minus units are for things that are bad, powerless, or quiet. An EPA profile is a list of three such measures: the first number represents Evaluation, the second is Potency, and the third is Activity.
Affect control theory works with mathematical equations to predict how events transform feelings toward or away from the sentiments which are evoked in a situation. Equations defining how events change feelings have been developed directly from research on people's responses, and additional equations have been derived mathematically from the change equations in order to define how new events can be formulated to move feelings closer to situational sentiments. But you don't really need to know those details in order to use Interact. Interact doesn't require that you deal with equations at all.
In fact you have enough theory now to comprehend how to use the program. It's time to learn how to make a computer do social psychological analysis!