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Biology of Positive Psychology: the influence of the body on the mind

"We do not laugh because we are happy.
We are happy because we laugh. "
- Dr Madan Kataria -

Psychologie Positive Grenoble Camille Lamouille

Do you know the proverb that says "Smile and life will smile back at you "? It seems simple and naive? This proverb relates to the concept of autosuggestion invented by the Coué Method and the positive thinking branch. To say that Positive Psychology is the same thing as positive thinking would make any initiate hopping mad. Yet not everything is to be thrown into positive thinking: I do not know if the fact of smiling engenders a positive return of life, what I know is that smiling will certainly increase our level of happiness. And how can we check it? By biological research. If we were convinced that the mind has an influence on the body, we know today that the body has one on the mind. Let me tell you the biological story of Positive Psychology.

I. Vagus nerve and Oxytocin: the love nerve and the moral molecule

Positive Psychology is not positive thinking. Why? Because the discoveries of Positive Psychology are all scientifically validated, while positive thinking is based on unproved popular theories. So, as a Positive Psychology practitioner, it is important to me to present you the scientific research proving that our body plays a role in our level of happiness.

Psychologie Positive Grenoble Camille Lamouille

The vagus nerve is the longest nerve in the human body. It connects the brain to a multitude of organs such as the heart, lungs, liver, intestine. It thus influences breathing, digestion, heart rate ... but also, and this is what interests us here, on our level of happiness. It is one of the great mind-body connections of the human nervous system. Dr. Stephen Proges, who has focused most of his research on this vagus nerve, calls him "the love nerve ".[1]According to research, people with a stronger vagus nerve (measured and indexed by heart rate variability) experience more positive emotions on a daily basis, build stronger relationships, cooperate more, have better results at school, are more selfless, and feel more compassion towards others. All practices of Positive Psychology can stimulate this vagus nerve by regulating the variability of heart rhythm (meditation, mindfulness, journal of gratitude, 5 acts of kindness ... see my last article about this[2]).[3]

When stimulated the vagus nerve will release norepinephrine, like dopamine and serotonin, which allows to feel more positive emotions, sleep better, learn faster, and be happier overall.[4]

The vagus nerve is connected to the receptors of oxytocin, which is a neuropeptide, in other words a hormone, responsible for happiness and social connection. Scientists have known for a long time that oxytocin plays an important role in the mother-child relationship during childbirth and during breastfeeding. New research shows that the role of this hormone is much larger than that. Oxytocin is responsible for our ability to create social bonds, our ability to be kind, to trust strangers.[5]Oxytocin can also reduce our stress levels, lower our blood pressure, increase our resistance to pain, enable us to heal more quickly and soothe our cardiac output.

Psychologie Positive Grenoble Camille Lamouille

Now that we know that happiness is also biological, how does the body change the mind? In other words, if we claim to be bodily happy, does it really make us happy at the level of the mind? Like Tarzan, who, persuaded to be a primate, has finally become one himself, we can bodily claim that we are happy to finally become one.

II. Fake it until you become it

On the last evening of my creativity training in Sestri, activities were organized in the main hall. Walking around a bit in this creative souk, I am surprised seeing a group bursting out laughing.The exercise consisted in forcing oneself to laugh once, then twice, then thrice ... until 12. What at first was a forced laugh finally turned into general hilarity.

Psychologie Positive Grenoble Camille Lamouille

This activity is a good illustration of the fact that by forcing oneself to smile, we release oxytocin, a hormone that makes us happy. Similarly, another exercise to achieve a similar result is to hold a pen in our teeth, forming a forced smile that will release hormones of happiness ...

Our nonverbals govern how other people think and feel about us, but our nonverbals also

Psychologie Positive Grenoble Camille Lamouille

govern how we think and feel about ourselves. It goes both ways. American social psychologist Amy Cuddy has proven that adopting so-called "high power poses”[6]for 2 minutes can increase people's testosterone levels by 20% (a hormone that reinforces feelings of confidence in itself and optimism) and decreases cortisol (stress hormone) by 25%. On the contrary, people taking "low power poses"[7]for 2 minutes have their testosterone levels decrease by 10% and their cortisol levels increase by 15%.[8]

My sister who called me three minutes before a job interview asking for a Positive Psychology advice to feel more confident was disconcerted by the banality of my response inspired by this biological discovery: stay for two minutes hands on hips, back straight and chin raised. At the end of her interview she calls me telling me that she showed them who she really is, with confidence and assertiveness. As a result, she started her new job a week ago!

In short, as Amy Cuddy would say, to increase your level of happiness: "Fake it until you make it. Fake it until you become it!”. Invest relationships, connect, feel positive emotions to be in better shape; and at the reciprocal take care of your body to be happier.

Psychologie Positive Grenoble Camille Lamouille

- Camille Lamouille -

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[1]Stephen Porges, Polyvagal theory


[3]“The Neurobiology of Grace Under Pressure: 7 habits that stimulate your vagus nerve and keep you calm, cool, and collected”, Christopher Bergland, Psychology Today, Février 2013

[4]“How the vagus nerve operates in the immune system inhibiting inflammation and stress”, Dr Sircus, Janvier 2015

[5]Research of Kosfield on oxytocin: in this scientific literature Kosfield and colleagues had people play a game wherethey got to give resources to a stranger and that stranger would get to give things back, and prior to the participant giving a gift, the participant either took a whiff of oxytocin in a little nasal spray or a whiff of a saline solution and what they found is that half of the people who took a whiff of the oxytocin literally gave away the max amount of their money while the control group only gave away 20% in the control condition. So Oxytocin is seemingly to produce trust towards strangers.

[6]High power poses is about Opening-up: we make yourself big, we stretch out, we take up space

[7]Low power poses: we close-up, we wrap ourself up, we make ourselves small, we don’t want to bump into the person newt to us

[8]Amy Cuddy, « Your body language may shape who you are”, Ted Conference, 2012,


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