Ninety percent of the movie takes place inside Riley’s noggin and while the filmmakers clearly took liberties with the characters – Joy, for instance, is, a bug-eyed, blue-haired sprite with the voice of comedian Amy Poehler; and a plump, bespectacled Sadness is the sotto voce of “Office” alum Phyllis Smith – they also nailed some key concepts in neuroscience.
Writer-director Pete Docter freely admits the inspiration for the film was his now-16-year-old daughter who, five years ago, confounded Docter with her inexplicable mood changes. To write a screenplay in which he was visualizing states of mind, Docter consulted psychologists and boned up on the latest brain science.
“This whole world is made up so we wanted to base it in as much truth as possible,” he told reporters in April.
Early in the movie, the formerly sunny-dispositioned Riley is suddenly confounded by her family’s relocation from Minnesota to San Francisco. In response, her emotions quarrel with each other inside "headquarters" for the right to "drive" Riley's brain.
For a pre-teen in turmoil, the emotions really are in control, say pediatric neurologists, primarily because their brains are not yet fully connected. The white matter that links regions of activity in the human brain isn't completely laid down until a person's late 20s, and the last region to be fully wired is the most important, the prefrontal cortex. This is the seat of executive functioning where we deliberate, plan, reflect and understand, and it's not even close to being fully wired in an 11 year old.
Memories are all-important in the life of Riley as she navigates a new school, new classmates, even a new climate -- she's an avid ice hockey player. What the movie calls "core" memories are fundamental to her well being, memories of past friends and experiences. Neuroscientists, philosophers and psychologists all say that memories are indeed an integral constituent to a person's sense of self, which is why Joy and Sadness are at odds as to who gets to "color" Riley's new life. And while in reality there is nothing called a "core" memory, neuroscientist Antonio Damasio, director of the Brain and Creativity Institute at the University of Southern California, describes something related. His "core consciousness" is the awareness of one's thoughts or feelings, which is necessary to place those memories of the past in context.
"Personality islands" also occupy territory inside Riley's brain. They include friendship, family, honesty, even goofiness.While there are no such discrete regions in the human brain, what the movie gets right is that aspects of our personality do not reside in any one place, but rather are distributed throughout the cortex and contribute to the architecture of our consciousness.
At night, when Riley goes to bed, her "headquarters" shuts down, and her memories from the day are loaded into a vacuum tube and shuttled out for "long-term" storage. Human memories are packaged for shipping in the hippocampus, which is shaped like a seahorse, not a vacuum. Long-term memories, specifically autobiographical memories are consolidated during the REM stage of sleep, something all the emotions in "Inside Out" are aware of, and then distributed for long-term storage in other parts of the brain. And while there are no "core" memories, as there are in the movie, in reality, those that are most entrenched are often the ones most colored by emotion.
As they voyage through Riley's brain, Joy and Sadness meet the "mind workers" who perform maintenance by clearing out old events into a "memory dump." "If Riley doesn't care about a memory it fades," we're told, and for a child about to enter puberty this is especially true. The brain during the teenage years is particularly fertile and primed to learn, which is why it is easier at this time of life to take up a foreign language or a musical instrument or a sport.
But the adage "use it or lose it" also holds. Unless Riley repeats what she's learned, re-visits her memories, they will fade -- the unfortunate fate of Riley's childhood imaginary friend, Bing Bong. Part elephant, part cat, he's made out of cotton-candy and speaks "fluent dolphin," but Riley is growing up and no longer needs Bing Bong for emotional or imaginative sustenance. The intrinsic connection between sadness and joy is one of the more poignant lessons of the film, one that Docter's daughter, Elie, likely learned for herself. She's still growing up, and when she viewed the film for the first time, according to the director, she "teared up."
Likely Joy and Sadness were both at the controls.