The theme of the film is that our emotions bring us together - storing things up and claiming to be happy all the time doesn't actually connect you with people on a deeper level."
But does the film accurately reflect primary human emotions?
Psychotherapist Dr Dacher Keltner, from the University of California, who was a consultant on the film, says what it gets right is the idea that emotions oscillate.
"There will be a time when your mind is filled with fear - a second or two before shifting to anger. The movie portrays that struggle over the control panel that I feel to be true scientifically."
And so far, Pixar's foray into psychology is winning audience hearts as well as their minds - not to mention their wallets.
Since its US debut a month ago, Inside Out is nudging the half-billion dollar mark (£320m) at the box office, putting it on track to become the most successful Pixar movie.
The Independent called it "an instant classic" while the Radio Times noted that "Pixar... never fails to locate the sweet spot between stylish smartness and tear-jerking goofiness".
But Docter thinks that the real success of Inside Out can't be measured financially. "It's a first for children at a pivotal age, and it's about someone relatable, not a superhero or fairytale characters.
"A movie that can tell little girls that it's hard to grow up and it's OK to be sad about it is actually profound."
Inside Out is released in the UK on 24 July