Riley is a pre-teen girl who lives a happy life in Minnesota playing hockey and spending time with her friends and loving parents. All that abruptly comes to an end when they move to San Francisco for her father’s career and a lot of things go wrong, starting with a delay in the delivery of their furniture that forces Riley to sleep in a sleeping bag in a depressingly bare room. Even her best friend back in Minnesota seems to have moved on with her life, and Riley takes it all very hard.
We see this played out in her mind, where her governing emotions Joy (voiced by Amy Poehler), Sadness (Phyllis Smith), Anger (Lewis Black, of course), Fear (Bill Hader), and Disgust (Mindy Kaling) try to deal with the internal consequences of her external stress as they watch the major aspects of her previously happy personality gradually fall apart.
The interior world is more cartoonish in appearance and much more comic in mood than the exterior, though serious stuff happens inside as well. As usual there are numerous hidden references to Pixar and Disney and a lot of attention to fine detail in the art as well as in the story development process. Neuroscientists and psychologists were brought it to talk about how thinking actually works, and while the film makes no attempt to represent that accuracy, there are references to it, such as having short-term memories moved into long-term storage during sleep.
The premise has things in common with the sitcom Herman’s Head (1971) and the personified organs in the last and best segment of Woody Allen’s Everything You Always Wanted to Know About Sex *But Were Afraid to Ask (1972), which in turn was a parody of Bell Labs science specials from the 1950s (in particular Hemo the Magnificent, originally broadcast in 1957).
A British comic strip called The Numskulls, which dates back to 1962 and is now published in a children’s magazine called The Beano, is also about characters inside someone’s head (someone named Edd). These characters personify functions—thinking, vision, and so on—rather than emotions, but huge numbers of people in the UK insist that Inside Out is a deliberate ripoff of The Numskulls. The strip’s creators dispute that, but they did publish a strip about it you can find here.
Of course, Inside Out’s antecedents go back a lot farther, at least to such works as Piers Plowman and Pilgrim’s Progress, in which the characters are personifications of abstractions and traits. In fact, Inside Out may come closer to a Christian allegory with the religion left out than to anything else.
I don’t think its Pixar’s best movie, but it’s pretty good and I recommend it.