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In the last 20 years, many psychology researchers have found evidence that we have three cognitive, decision­making brain systems. I will call them the reflecting brain, the reflex brain and the archiving brain. Ideally they collab­orate for an optimal intellectual performance, although sometimes they compete with each other.

I’d first like to give you a summary of the key features of these brain systems because it is difficult to explain any one of them in detail, without referring to the others.


We are constantly thinking. This con­stant self-talk is about what we are doing, the situation, our goals, our­selves. The French philosopher Descartes said: Cogito ergo sum, I think, therefore I am. But the reverse is just as true: I am, therefore I think. Sum ergo cogito! As I described in my book “Stress: Friend and Foe”, this inner chatter even has an important influence on our emotions, behavior and body.

This thinking happens in the brain system that I call the reflecting brain.

The most important and uniquely human quality of the reflecting brain is that with it we can think about things that are not actually present, things that do not even exist. Hence it is not only able to think about the present but also about the past and the future. We can think, fantasize and invent stories. This brain system is responsible for conscious reflecting, logical, analytical and synthetic thinking, creative think­ing, problem solving, thinking ahead, reflecting on the past and deep think­ing.

This reflecting brain is slow, it needs sustained attention and concentration, and because of this it consumes lots of energy and easily becomes tired. For the purposes of this book it is very impor­tant to note that the reflecting brain can only handle one thought at a time; as such, it is like a serial processor.

The reflecting brain can think long­term, set long-term goals and be proactive, something that no other animal is capable of. For these reasons, psychologists sometimes call it the “goal-oriented brain", in contrast to the “stimulus-oriented" reflex brain.

One of the things that is uniquely human about the reflecting brain is that it can take precedence over our reflex brain. For this reason, this reflecting brain network is sometimes called the control network or the controlling brain.


The oldest of the three systems, in evolutionary terms, is very fast, uncon­scious and autonomous. For the purpose of this book, to make reading and remembering easier, I will refer to it as the reflex brain, because it is as fast as a reflex. In psychological research it is often called “the stimulus-driven sys­tem". It is a kind of “snapshot brain" because its conclusions are in an extreme way based on the here and now and nothing else. In his excellent book about this brain “Thinking fast and slow" Daniel Kahneman calls this “What You See Is All There Is": WYSIATI. I prefer to call it “SNIA": Sensory Now Is All, because what exists for our reflex brain is not only what you see here and now, but also what is immediately present in the sensory world of hearing, smell, taste, touch, balance, tempera­ture, pain, acceleration and body awareness. As a result, our reflex brain is totally reactive, unable to be proactive or reflect on what has happened.

This brain can process many inputs at the same time, it does not consume much energy and it is lightning fast because it works with many genetic and acquired shortcuts. The natural, geneti­cally defined tendency is that our fascinating primitive reflex brain reacts faster than our fantastic reflecting brain. This was a big advantage for the survival of our human ancestors in their life or death struggle in the savan­nah a few million years ago. Yet it is often a liability in the jungle of the 21 st century because the speed of this sys­tem comes at a price: if we don’t give the reflecting brain the opportunity to check its rapid conclusions, the reflex brain makes a lot of irrational mistakes.

Part of this reflex brain is the affect- network. Emotions too activate super­fast shortcuts that are very useful in many situations, so useful in fact that managers and other professionals should use them better by reflecting on them, rather than ignoring them. On the other hand, as we all experience regularly, emotions can cause major problems if they are not controlled or guided by an emotionally intelligent reflecting brain.

A feature of our reflex brain that was important for our survival in the savan­nah, but that causes lots of problems for brainworkers today, is that its attention is unconsciously captured by novel or sudden sensory changes, such as smells, sight and above all sounds. This atten­tion to stimuli, even when it's uncon­scious, interferes not only with the conscious attention that our reflecting brain needs in order to do its thinking, but also with the work of our archiving brain that tries to store the information in our memory. What’s more, each time a stimulus captures the attention of our reflex brain we get a little shot of dopamine in our brain, which may stimulate us to seek out these stimuli and even become addicted to them. This explains to some extent why people can become addicted to the continuous stimulation of ICT gadgets in their pocket. (Much more on this in the fol­lowing chapters.)

In the table below I summarize the most important differences between the reflex and the reflecting brain systems.


Every day our brain takes in billions of bits and bytes of information. The brain cannot afford to throw all this data into one big pile. It has to be ordered and stored in such a way that it is available for future use. This filing away is done by our archiving brain, which is like a team of millions of tightly connected librarians, archivists and cataloguers, who have only one client: you, or rather your reflecting brain. They take in the billions of bits and bytes coming from the outside world via all our senses, together with the ideas generated by our reflecting brain, and then decide what to discard and what to store in our long-term memory. They stockpile this information in associative ways that are still unknown.

Recent research seems to indicate that the fact that older people need more time to retrieve information from their “archive” is more related to the fact that their database is so much fuller than that of young people. The longer retrieval time is therefore normal and predictable in a mathematical model, rather than the result of a deterioration of the memory system.

Modern functional brain scans show that the reflecting brain and the archiv­ing brain are in balance: when one is activated, the other is deactivated and vice versa. As we will see further on, they compete for time and space in our working memory, a part of our brain that can be compared with the central microprocessor in a computer. The archiving brain is always active, always on alert; therefore it is sometimes called the “default-mode”. It never rests, un­less our reflecting brain occupies all the processing power. While the reflecting brain can and should take regular breaks and sleep, the archiving brain will jump at the slightest opportunity of a tiny little bit of free processing power to do its job. Because it is most active when there is no specific cognitive task to fulfill, researchers sometimes call it “task-negative”, contrasting it with the “task-positive” reflecting brain. The archiving brain becomes most active when its only client, the reflecting brain, leaves it alone and sleeps or takes a break, even a micro-break of a few minutes or seconds.

Theo Compernolle

“BrainChains: Discover your brain, to unleash its full potential in a hyperconnected, multitasking”

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