Some video games develop hippocampus, others develop caudate nucleus. The development correlates with the increase of volume of grey matter either in hippocampus or caudate nucleus.

The development is a result of training of a relevant device which the game requires the player’s brain to use: either brain’s GPS system (hippocampus and cortex) or brain’s autopilot system (caudate nucleus and cortex).

Our brain spontaneously selects which device to turn on. We can’t make a conscious choice.

Hippocampus acts as a switch between the two devices. It turns the GPS on in ambiguous environments and the autopilot on in predictable environments.

The brain uses Bayesian reasoning and statistical computations to estimate the level of ambiguity in the environment. It’s approach differs much from our common sense and conscious logic.

The brain considers ambiguous any environment without a known structure. It doesn’t matter for the brain if you consider your studies, job or travel very cognitively challenging. If they have a known structure the brain puts an autopilot on.

Let me give you some examples. If you know the rules of the game and they never change it doesn’t matter how hard you practice - your brain just turns on and trains its autopilot. If this text would have highlights in the beginning they would provide you with its structure and let your brain to turn the autopilot on to save energy and computational resources.

The biggest challenge for the brain isn’t the entirety new environment but the environment with a known structure in which the structure suddenly change. Our brain monitors the environment constantly looking for early warnings of such a change which signal that the autopilot should be immediately turned off and the GPS turned on. Both devices use the same parts of cortex. Thus they can’t be put on simultaneously.

There are plenty of situations, in which it is possible to use either GPS or autopilot. Brains with a well developed GPS device prefer to begin with turning the GPS on in such situations. Brains with less developed GPS prefer to rely on autopilot from the very beginning.

People with brains which prefer the GPS are motivated by the desire to play. People with brains which rely on the autopilot are motivated with winning. The former will keep playing when the environment provides them with enough challenges (in the brain’s sense). The latter will need quick wins to stay engaged. It happens because the two devices rely on different dopaminergic feedback loops. The GPS uses a long loop connecting many stimuli with each other while the autopilot uses the shortest stimulus->response connection.

Different preferences of our brains create a lot of confusion among neuroscientists and psychologists. People with different preferences perform differently on the same tasks. Results become controversial. That’s why it is still hard to say what should we do to train our GPS devices.

They need some training indeed because more skills we learn and more habits we obtain, more and more time we spend on autopilot. We use well structured information, play well structured games, watch well structured movies, use well structured interfaces and take well structured trips. Structure is everywhere and it isn’t changing unexpectedly much, only self-improving.

Our autopilots receive even excessive training unlike our GPS devices but the GPS is crucial to control and guide the autopilot. Both systems evolved in animals to successfully navigate physical spaces but we, humans, took them several steps further. We use them to navigate our moral and social virtual environments, the environments of meaning and thought.

Almost all healthy kids are spontaneous GPS device’s users. They exploit its ability to extract structure from uncertainty to relentlessly explore the world around them. It’s pure speculation but it looks like autism spectrum disorder is somehow connected to the premature autopiloting preference developed by brains of those kids who didn’t have enough access to unstructured environments.

In adolescence we get the first time acquaintance with the temptation of habits and try the autopilot device that is not yet properly integrated with the GPS device. The integration takes place through frequent switching between predictable and ambiguous environmental conditions. Teens who have enough of predictability around become relentless ambiguity seekers. Those with underdeveloped GPS or delayed integration succumb to bad habits - addictions of all sorts.

Hippocampus is shrinking with age in all mammals. However in humans it’s shrinking faster than in animals. We are the champions in structuring of the environment but it has cost, the GPS device. Do you need your own GPS device if you have Uber for everything? We are today living much longer in a much better structured environment than our ancestors. Pure speculation again, but doesn’t it seem obvious that Alzheimer’s and dementia became so common because many people keep living with their GPS device already turned off?

Plenty of pro gamers became furious when some rules of game Fortnite were changed without notice only a couple of weeks before the major Fortnite e-games tournament. Pros were complaining that they wouldn’t have enough time to train their autopilots. I guess the secret of Fortnite’s stunning success among teens is exactly in such abrupt structural changes because they create ambiguity to which teens are flocking in droves.

Fortnite provides a very good example of how a video game can do both good and bad to our hippocampus. It’s still an autopilot focused game with some GPS teasing tweaks. Of course, we’ll see controversial results if we try to measure hippocampal grey matter dynamics of players. Most probably the hippocampus will grow in those players which already have GPS preferring brains. And it will further decrease in those with autopilot preferring brains.

A group of scientists from McGill University has been using tasks in a virtual 3D maze (built on Unreal platform) to accurately detect the brain’s preference already for more than a decade. Developing a free mobile app on the basis of their solution and experience may become an important first step in making people aware of the GPS/autopilot problem and helping them to start successfully tackling it.

There’s more on stake. We are all sharing one real world. Our unshared experiences in it make us what we are as individuals. Unshared experience emerges from our brain’s reaction to ambiguity. In a well structured shared environment all experiences are shared. Such an environment erases individuality or doesn’t let it to evolve.

We need another world, a parallel world for us all to share in which ambiguity will be the king. It could be Mars but we can’t all travel there and we may not necessarily wish to risk our physical survival there. For me it’s obvious that losing personality is the same as losing one’s life. Hence the time may come when people will be ready to risk their lives for the sake of staying themselves. Before that will happen we can offer them a better alternative - a virtual world enriched with ambiguity.