I recently saw the new Pixar movie, Inside Out, which follows the inner workings of a young girl’s mind. (I will be discussing the premise, rather than the plot, of the movie so only mild spoilers.) As a neuroscientist of course I was interested in the metaphors that the writers chose to represent the workings of the human brain. They made many good choices, but there was also some interesting elements missing or misplaced.

Of course, I understand this is a movie. The writers made choices to make the movie enjoyable to children as well as adults, which means they likely made some choices to keep things simple. Other choices may have been driven by the needs of the plot, and still others simply to be cute and entertaining. I get it – this wasn’t a neurology lesson. For example, IMDb notes:

“The writers considered up to 27 different emotions, but settled on five (Joy, Sadness, Disgust, Fear and Anger) to make it less complicated. Some of the major emotions that ended up being cut included Surprise, Pride, and Trust.”

Central Command

But let’s explore the choices they did make, which to some degree reflect popular understanding of the basics of brain function (and is also just a fun way to talk about neuroscience). In the movie the writers use the metaphor of a command center with a control panel. For a newborn infant the control panel is a single button. As people mature the panel gets more elaborate, with more nobs and levers. The control panel is operated by different emotions. I like the metaphor of a specific emotion being “at the controls.”

The control panel itself, however, is not a good metaphor (and again, at this point I am talking about neurological accuracy, not the demands of the script and an entertaining movie). There does not appear to be any equivalent of a command center or control panel in our brains. There is no “seat of consciousness” or “global workspace.” Rather, consciousness appears to be highly distributed, with each part of the brain contributing its little bit.

The closest thing we have to a “command center” in our brains is the frontal lobes which provide executive function. These frontal networks allow us to inhibit our behavior, strategically plan our actions and goals, and act in our own long term interests. The emotions do not reside here. They live in the deeper (and more primitive) limbic system.

If I were designing a cutesy Inside Out – like metaphor for brain function, there would be multiple distributed “control panels.” There would be a raucous committee all simultaneously clamoring for control. On the lower deck would be the emotions, and next to them basic drivers like hunger. On the upper deck would be various aspects of executive function and the higher cognitive functions. These elements would be in frequent conflict, sometimes emotions winning out, at other times executive function controlling, or at least ameliorating, the emotions.

When different brain metaphors are in strong conflict then the environment could turn red with cognitive dissonance. Perhaps executive function, like a troubled monarch who has little control over their rebellious barons, has a slick adviser whispering in their ear (think Grima Wormtongue from LOTR, or a corporate attorney advising their client.) Wormtongue is the voice of rationalization, telling executive function how to make the cognitive dissonance go away by accommodating the emotions.

Executive function was completely missing from the Inside Out metaphor, and instead the emotions had direct access to the top-level control. This might have been a better metaphor for a reptile than a primate.

Personality

In the movie, personality was established by specific core memories and represented by “islands.” For example, the character had a core memory of making her first goal in hockey, establishing “hockey island” as a strong aspect of her personality. This metaphor was completely plot driven, and has no real analog in neuroscience. It is worth mentioning, however, because it is based on the assumption of the “blank slate” – the idea that people are born essentially blank and our personalities are crafted entirely out of our experiences.

This is an outdated concept. It is generally recognized within neuroscience that personality is strongly genetic and deeply coded in the brain. Obviously, there is no absolute “nature” or “nurture” and brain function is always a complex combination of inherent and learned factors. The brain is an organ that evolved specifically to interact and adapt to the environment. It also displays plasticity, meaning that it can slowly change its wiring over time based upon use and experience.

Core personality traits, however, seem to be very stable and resistant to change. They also seem to be more determined by genetics than memories.

A better metaphor for personality, therefore, could have been the architecture of the metaphorical “buildings” and structures in the brain. The design, functionality, decor, condition, tidiness and mood of the environment could convey personality, and also be stable but able to slowly change over time. Another way to represent personality could be the size and dominance of the various emotions. An angry person, for example, might have had a big hulking “anger” emotion, dominating the other emotions, and even bullying executive function.

The core memories and islands in the movie are a better metaphor for culture and ideology, which sits on top of personality. Culture and ideology are learned, and can experience a crisis which causes aspects to collapse. They also change and evolve over time more similar to the islands in the movie.

Memories

Memory was handled in a predictable way in the movie, with some good and bad aspects. I liked that memories were formed and tinted with specific emotions. I also like that memories were consolidated down to long term storage during sleep. Memories also faded over time and really faded memories were eventually dumped. One of the funniest bits in the movie was a memory of a commercial jingle, which was recalled up to central command at random times.

Otherwise, the memory metaphors did not really work. Each memory was a small glass globe, as if it were a discrete thing. In reality memories are highly networked and interconnected. They are also very malleable. In the movie a specific memory could be played back with absolute fidelity.

Rather than globes I would have used something far more transient and changeable, such as bubbles. The bubbles link up to other bubbles, fuse, morph, and also are changed by the act of trying to access them. The memories should not have been hard solid objects, but living changing interconnected things.

Misc.

One funny moment in the movie is when a box of opinions and another box of facts spill and get all mixed up. One character says not to worry, just put them back all jumbled, it happens all the time. Indeed.

Conclusion

I loved the movie. It was very enjoyable, and I highly recommend it. If you have children the movie is especially sweet (which is usually the case with Pixar).

As a metaphor for brain function, the movie was highly problematic. Mostly accuracy was sacrificed for the plot and to keep the movie simple and entertaining. However, it is a very interesting thought experiment – how to design a metaphor that accurately captures brain function according to our best current knowledge. I do hope the movie motivates people to think about brain function, but I fear it will increase some poor brain metaphors in the public consciousness.