By Dr David R Hamilton | Source
Imagine you’re having a regular day, feeling neither happy nor sad. Then you meet up with a friend who is buzzing with excitement about something great that’s just happened to them.
Without even trying, you start to feel a little lighter, a little happier. What if I told you this isn’t just a coincidence, but a well-documented scientific phenomenon? And the further effects are quite astonishing.
Scientists James Fowler and Nicholas Christakis studied data from thousands of people in a large social network and found something incredible: happiness is contagious.
For example, if someone you are friends with becomes happier for some reason, then there’s a fairly decent chance that you will also become happier over the next few weeks or months.
They even put some numbers on it. If it was an immediate social contact who became happier, the chances of you becoming happier were 15%. But this was an average of social contacts in general, people you know and interact with from time to time. If the person who became happier was someone you considered a friend, then the chances of you becoming happier was 25%.
And if this friend was a close mutual friend, and who lived within a mile of you, the chances of you becoming happier if they became happier increased to 63%.
How is this even possible?
Well, there’s two main factors. One is emotional contagion and the other is behavioural contagion. And they both fit under the umbrella of social contagion.
Emotional contagion
Emotional contagion is the phenomena where we ‘catch’ the emotions of people we spend time with, just as you can catch a cold from someone you interact with. It’s facilitated by a network of brain cells known as the Mirror Neuron System (MNS).
When someone you’re with smiles, your MNS picks up their facial muscle movements and automatically triggers the same ones in you.
That’s what the ‘mirror’ bit means. It’s why you tend to smile when someone smiles, frown when someone frowns, even tense when you see someone looking fearful.
But this is only half of it. At the same time, your MNS pings the emotional regions of your brain that are consistent with the smile, so you not only smile but you also feel a bit better.
In this way, if they’re smiling because they feel happy about something, within seconds you find yourself smiling and feeling happier too.
Behavioural contagion
With behavioural contagion, we become happier when someone’s behaviour around us changes. So if your friend becomes happier and starts behaving differently, their happier behaviour has a knock-on effect on you.
For example, maybe they want to go out more, share more coffees and conversation, go to the cinema. As you go along, these experiences result in you becoming happier too.
It can also be caused by imitation. For example, say your happier friend tidies their garden and decorates their home because of how they’re feeling, you may well get the urge to do the same yourself, and reap the rewards of satisfaction at the extra cleanliness and colour in your life.
Contagious happiness tends to work through both these pathways.
And it depends on the quality of relationship. It’s much stronger if you are close friends, but less so if a friendship is one-sided. For example, if someone thinks of you as a friend but you don’t see them in the same way, then there’s only a 12% chance of their happiness impacting you.
The ripple effect
Where things get really interesting is that happiness can spread much further than from just one person to another. Happiness actually spreads up to what’s known as 3 degrees of separation.
This means that if you become happier, you will increase the likelihood of your friends becoming happier (1-degree), your friends’ friends (2-degrees), and your friends’ friends’ friends (3-degrees). And most likely you have never met, nor will ever meet, most of the people in this latter group. Yet your change in happiness affects them.
That’s amazing! To put some numbers to it, starting with the 15% average figure I mentioned above, which is the likelihood of your contacts (in general) at 1-degree of separation from you becoming happier if you become happier, Fowler and Christakis found that people at 2-degrees of separation from you stand a 10% chance of becoming happier because you have become happier.
And that’s the fascinating bit: because you became happier. Not for some other seemingly random reason. But because you became happier.
And then it extends farther. People at three degrees of separation from you – remember, these are your friends’ friends’ friends – have a 6% chance of becoming happier because you became happier.
Let’s put this into perspective. Say you have ten friends and each of them have ten friends, so that’s 100 people at two degrees of separation from you, and each of these people also have ten friends, that’s 1,000 people at three degrees of separation from you.
So roughly 60 of these people will find themselves feeling a bit happier over the next few weeks or months because you have become happier, either through emotional or behavioural contagion.
If you ever doubted how deeply connected we all are, just let those number sink in for a second.
So the next time you do something that lifts your mood – a walk in nature, a heartfelt conversation, an act of kindness – remember that the benefits may extend far beyond yourself. Your happiness might just be the spark that ignites a wave of joy for people you’ll never even meet.
Resources
The main reference for the 3-degrees of separation research is: J. H. Fowler and N. A. Christakis (2008), ‘Dynamic spread of happiness in a large social network: longitudinal analysis over 20 years in the Framingham Heart Study’, British Medical Journal, 337, a2338. Link to study.
If you want to read more about contagious emotions and experiences (happiness, depression, fear, loneliness, weight changes, divorce), how it works, how it happens in the workplace, even how playing violent computer games or watching violent movies can affect us, see my book, ‘The Contagious Power of Thinking’. Ref: David R Hamilton PhD, ‘The Contagious Power of Thinking’. Link to book on Amazon UK Link to Amazon US Amazon Australia Amazon Canada (it is available in some other countries too).

Very interesting, although I suspect this is but the tip of the iceberg about how inter-connected we all are. I will also add, that if hapiness is contagious, misery is probably as well.
Which is not to say that we should repress so-called negative feelings. Sometimes, sharing negative feelings with a friend can uplift us both.
Agreed, Raksha, to open up and share something human, not glamorous, forms deeper bonds.
This report is too simplistic, though.
When someone is happy about a win they’ve had, maybe they’re just telling about it, it’s good news…
but this is earth, 50% of the time, they’re needing to be bragging and boasting on themselves, to feel bigger and better than the listener!
Haha, the survey didn’t dig deeper, and this Hamilton guy, chose not to either; no offense to him, he may be conditioned to just accept “scientific data”.
I’d say these two scientists went in with a limited perspective 😂
💎 I don’t feel jaded, more like…seasoned🤔
Yeah. Just yesterday, I had a hard time, and I talked with my best friend, and after I asked, she said she was uplifted as well.
There are some mathematical errors in this post as well. Because if you take 3° relationships, chances are, that there are a few who are redundant. But I am not an extremist in that regard so I enjoyed the notion itself.
But yeah, sharing our shadows or negative feelings can also uplift us, if we are not just into victim mode but actually pourring light(consciousness) into the shadows.
Clearly, the Toyota ads stereotype is not genuine hapiness.
I have read on era lots of times, Raksha, that our energy bodies (I think) are large, and overlap easily with others, so our moods can travel that way.
I’ve worked out a ton of my shadows on poor era🤭….not that I knew I had any!
I definitely see a pleasant difference in the behaviors of people around me, as I do shadow work.
Funny about the math errors😂
I actually agree with the article, we affect others within range, energetically, somehow 💎😁