If you were constantly living with some background noise, like indistinct chatter or traffic noise, would you notice it?

I lived in the peaceful South of France until my early 20s, then I moved to Shanghai, spending three years in the Middle Country. There, I was immersed in a city that never sleeps. Almost everything you could think of is accessible every day of the week, 24 hours a day.

At the time, the local news reported that more than 10 million people commuted daily in the city’s metro and its 400 stations. An unfathomable number of cars and scooters were constantly honking to signal their presence to others. The wind whipped through the endless streets and echoed the whole city’s agitation and ruckus. 

And yet, after a few months, I didn’t notice the “background noise” anymore.

I only realised when I went for an excursion in the Chinese countryside to explore the breathtaking Luxi Gorge. Walking along a peaceful river by day, we stopped at a small cabin in the middle of nowhere, and I slept on bamboo sticks, which was a memorable experience, especially for my back!

Surrounded by silence, my ears were ringing. It was as if I could not tolerate the surreal calm of the place. Eventually, something popped, and the noise disappeared, allowing me to experience pure bliss. 

Scientists studied this phenomenon, called auditory habituation, or in other words, how we adapt to ambient noise. 

In their experiments, they exposed mice to a constant, loud but harmless noise (similar to a lawnmower or hairdryer) for a week. Then, they compared their brain activity with those of mice that remained in a quiet environment. The scientists noticed a reduction in the number of neurotransmitters released in the auditory cortex, which meant that the sounds heard were not transmitted entirely1. 

Researchers tested how fast humans can adapt to ambient noise in an open office space and found it happens pretty quickly: in less than 20 minutes2, in fact. But unfortunately, even if we can filter out unwanted sounds, they can still have a negative impact on us.

According to the World Health Organisation, prolonged or excessive exposure to noise, whether in the community or at work, can cause permanent medical conditions, such as hypertension and ischemic heart disease3.

When Spanish researchers studied the health impact of traffic noise in Madrid, they found associations with increased stress levels, higher risk of depression and cardiovascular issues4. 

So, it appears we can get used to background noise and somehow tolerate it, even if this is detrimental to our wellbeing. And there is another background noise we accept and learn to put up with. It is a mental one and, if you bought this book, you probably know which one I am talking about.

Overthinking is like a persistent noise in your head.

We get so used to it that we don’t notice it anymore, even if it drains our strength. When we silence this ceaseless racket, we gain clarity. We feel re-energised yet appeased.

But beyond this metaphorical explanation, what is the scientific definition of overthinking? Is it really that bad? It seems there are benefits to overthinking. For instance, to make smarter decisions or ensure we have considered all our options.

With this in mind, I decided to research the difference between thinking and overthinking to see how I could help overthinkers.

I did more than 365 one-on-one interviews with overthinkers over a year. Indeed, this book would not be possible without the many volunteers who generously gave their time. In the end, there were more than 250 hours of qualitative data that I used to investigate this subject and come up with valuable and practical insights.

Based on this interview material, I came to the conclusion that there are three commonly held beliefs about overthinking which are false. I call them the three myths of overthinking. These are:

Myth 1: Overthinking is enhancing my thinking.

Myth 2: Overthinking is inconsequential to me.

Myth 3: Overthinking is inevitable in decision-making.

While conducting my research, I established a scale ranging from 0 to 10, where 0 means not overthinking at all and 10 means overthinking all the time. This enabled both the interviewees and me to rank their level of overthinking. 

When asked how they would rank themselves, the participants who believed all three myths ranked their overthinking level at seven or higher.

Those who held fewer beliefs ranked their overthinking level lower. It was particularly striking for the interviewees who viewed themselves as “recovered” overthinkers, namely as those who had successfully conquered their overthinking.

And the higher the level of overthinking, the more the participants were experiencing adverse effects, such as feeling unproductive, inefficient in their decision-making or socially anxious. 

At the highest level of overthinking, it’s not background noise anymore. Instead, it’s a constant aeroplane motor noise that runs in your mind—and it doesn’t go unnoticed. People reported experiencing chronic insomnia, crippling levels of stress and anxiety, and mental and physical exhaustion.

So, this book aims to give you the keys to turn down the noise volume, liberate yourself from the shackles of overthinking, and appease your hyperactive mind. 

But you might say: “I don’t want to think less; that would make me stupid.” 

You won’t.

Conquering overthinking is not about thinking less but thinking better.

As you finish this book, your thinking will be sharper and clearer, ensuring you make efficient decisions confidently. 

To get these results, we will debunk each of the myths of overthinking, explaining how they form, why they are harmful and the techniques and tools you can use to manage and negate their effects. We will also explore the six different overthinker personas (the Maximiser, the Finisher, the Observer, the Helper, the Dreamer and the Performer) that will help you better identify what triggers your overthinking and the specific behaviours that relate to it.    

Finally, as we methodically dismantle these beliefs one by one throughout this book, you will notice yourself overthinking less and less.

Before we begin, here are a few tips to keep in mind to get the most value out of this book.

Firstly, this book is going to challenge you. 

I wrote it to be engaging, daring and actionable. However, if you hold any of the false beliefs mentioned above, this will be confronting. The claims made in this book are backed by factual and scientific evidence, as well as my opinions and convictions after spending a great deal of time on this subject. Where research went against my conclusions, I did not exclude it in favour of research that supported my findings.

Secondly, I encourage you to approach the material in this book with a balance of “openness” and “scepticism”.

If you find yourself disagreeing with any of the ideas and concepts put forward in this book, try to be open-minded and give them the benefit of the doubt. It could simply be unconscious resistance stemming from your overthinking beliefs.

On the other hand, don’t patently agree with everything in this book. There will be sections that resonate with you and others that simply won’t. Test and see for yourself what is working best for you.