A Cycle of Predictions and Simulations

Lesson objective:

In lesson 12, we will discuss how our brain needs to be prepared to adapt quickly in the event of potential threats to our survival and safety, just like an airport control tower. It does so by creating mental simulations, a series of unconscious models of what might happen to coordinate and prepare an adaptive response.

So, we have a lifetime of experiences that have turned into associations. Various mental shortcuts, or heuristics, make it easier to recall and deploy associations that make survival easier. And on top of that, all of this information informs predictions that enable us to avoid and preempt possible dangers in the world around us. 

Rarely do we have all of the information needed to create an accurate prediction of what might come next. It would be wonderful if we always had assurance or certainty–but in the absence of certainly, it makes sense that our predictive brains err on the side of caution, just as it makes sense for the engineer in the control tower to err on the side of safety when assessing a new or unknown threat. 

As we said, in the absence of real, verifiable information, the brain  will usually fill in the gaps with information from past experiences and will rely on heuristics. Based on available and inferred information, your brain might:

  • predict something dangerous
  • create a mental simulation (an unconscious mental model of what may happen)
  • coordinate and prepare an adaptive response

And this is the rapid cycle of predictions and simulations that goes on in our brain. 

Importantly, your brain may simulate lots of possible scenarios about a given situation. 

For example, imagine you are walking at night, and you hear the rustling of tiny footsteps just ahead of you. It might be a dog, but it might not be. You do not have any way of knowing as it is dark and you cannot see. In this case, you need to make a guess. In the absence of information–yet suspected danger–your brain might simulate a bear, or a snake, or a wolf, or a dangerous person.

As all of these are possibly dangerous, your brain will start to prepare your body for meeting this threat. 

  • Your heart rate may rise.
  • Your breaths may shorten.
  • Your palms may sweat.
  • Your pupils may expand.

Again, no two people will react the same way to predicted or imagined danger. This is just an example. In any case, the brain will coordinate with the body to prepare the appropriate, adaptive response to deal with the predicted situation at hand—something dangerous.

Finally, you have to confront your prediction and simulation. You have to confront the unknown reality of the dog, the snake, the wolf, or whatever else it may be. You need to confirm your simulation. If it is something threatening, great, you are ready to run.

If it is not something threatening, and just a small, scared kitten, you have made a prediction error. In other words, you have simulated and prepared for a scenario that does not align with reality. In this case, your brain will re-evaluate the situation with new information: that the ominous noise was just a tiny kitten. In the case of a prediction error, you can adjust your response accordingly. This feedback cycle of prediction, simulation, response, and verification is important as we go deeper in our understanding of the brain.

The outside world and those around us do not see this cycle happening in us. Indeed, it happens so fast and so constantly that you yourself are probably rarely aware of the prediction cycles your brain is going through. It happens mostly automatically.

Each person’s brain is unique in the predictions it makes, just as each person is unique.

While these functions are unique to you, all humans share the same core purpose behind the predictive process. The reactions and behaviors that result from the predictive process in all of us share the same basic purpose—ensuring safety and survival in a world of risks.