Reason is usually in the "driver's seat", and is shown to be calm, collected and rational. Stuck in the back seat, Emotion just wants to indulge in every impulse. Emotion will overpower Reason from time to time, usually in response to external stimuli.
Reason and Emotion are also shown as female versions. Reason is caricatured as a prim and strict schoolteacher, while Emotion is a saucy, voluptuous sprite just looking for fun.
In Inside Out, director Pete Docter makes the situation much more complex: Instead of just Emotion and Reason, we have Anger, Disgust, Joy, Fear and Sadness. These five basic emotions influence a good deal of the young girl Riley's behavior, with Joy acting primarily as leader.
The Emotions reside in the "Headquarters" of Riley's mind, which somewhat resembles the bridge of the starship Enterprise. Here the Emotions record and store Riley's memories as colored spheres, each bearing the feeling of their particular situations: Joyful, Sad, Angry, etc. The memories are ultimately sent off to "Long Term Memory". The emotions manipulate Riley through their control console, primarily with a pair of bulldozer-style joysticks. They can also plug "ideas" into the control console, which are represented by light bulbs.
In a stereotypical way, Fear, and especially Anger, are shown as male characters, supposedly representing negative emotions. Disgust, Joy, and Sadness are shown to be appealing female characters, foreshadowing that even Sadness has a positive potential. Joy loves life, and sees everything as a happy adventure. Disgust keeps filth and things that might cause harm and displeasure away, while maintaining a chic sense of style.
The "Headquarters" of Riley's mind towers precariously over the "Memory Dump"; a bottomless pit where old useless memories are discarded, and are considered lost forever. "Headquarters" is connected to Riley's five "Islands of Personality". Beyond the islands is the vast labyrinth of "Long Term Memory" where the adventure takes place.
Riley's parents have almost identical situations occurring inside of their minds: The "Headquarters" of Mom's head is like a pleasant TV studio, with smooth shapes and warm colors. Here the five basic emotions also sit at a larger console, looking at the world through the mother's eyes. Sadness has the center seat of the control console, but she is supported by the others, and does not seem depressed the way Riley's Sadness is.
The five basic emotions basically resemble Riley's, except they have all been femininized, and wear glasses like the mother. These five are much more mature, and act in a more sophisticated manner. But from time to time, they still manage to cause trouble for poor old Mom.
In contrast, the inside of Dad's head is more like a military command center, very dark, or very "boss" and high tech, like the ultimate man-cave. The five basic emotions are all macho, male versions watching the action on a giant screen. In this "Headquarters, Anger has center seat, but Anger's reactions seem to be tempered by experience, and he needs the cooperation of the other four to maintain Dad's personality. Curiously enough, Fear is Anger's lieutenant, so that gives us some clues into the Fathers' background. (Each character also sports the father's mustache.)
Docter's other key story point was how our emotions colored our memories. This was a major issue for Joy, who was always anxious to keep Sadness from touching Riley's core memories, which would tint them in her sad, blue hue. Apparently, even emotions have emotions in Inside Out. And their own thought processes as well. While entertaining they were not always insightful when it came to supporting Riley's mind and personality.
Inside Out also reminded of the 1972 NBC TV show "Search" with Burgess Meredith. Here a team of experts help guide special "Probe" agents the way NASA's mission control technicians would support astronauts. But I'm getting off track. Inside Out was very dialogue heavy, and a bit slow in pacing to arrive at the crisis and climax points of the story. There was also the obligatory sacrifice of a character, in this case Riley's old imaginary friend Bing Bong. His "big goodbye" scene seemed a bit contrived and cloying. But I suppose they needed to kill off a character to show the audience that the situation was still serious.
Where was Reason, Love, Jealousy, Greed or Courage? Too abstract for the story? Or just too many characters to keep track of. Personally, I think the general concept of little people inside our heads is a bit overworked. I suppose this relates to the Archetypes of human personalities. Philosopher Alan Watts commented on this in one of his lectures, arguing that humans are a much more subtle combination of dimensions and elements.
Still, go and see Inside Out. I wouldn't devote this much work to a film I didn't enjoy. It's fresh, and much more original than all the sequels Pixar has produced lately.