I spotted the needy traveller in the lineup for security at San Francisco International. Having just relinquished her luggage cart, the woman was nudging a stroller containing a sobbing toddler while wrestling with an overstuffed shoulder bag, a backpack and what looked like a load of groceries. She was a walking traffic jam – exactly the kind of nightmare most frequent flyers try to avoid.

I caught up with her after she made it through security. Wisps of sweat-soaked hair were pasted to her cheeks.

"You need help!" I declared. Startled, she looked up, then eyed me from head to toe. After all, what kind of a nut tries to help a complete stranger in an airport these days?

Illustration by Pascal Blanchet

"We gotta move," she said, slinging a couple of bags my way. We charged down the steel-and-glass concourse of the international terminal, barely speaking until we reached her gate. The plane was boarding. She thanked me breathlessly as she hauled her little boy from the stroller and receded into the crowd.

I paused there for a moment to record my psychophysiological state. Heart rate: slowing. Feelings of stress: zip. Happiness, on a scale of one to 10? Oh, at least a nine.

I felt great, especially considering I was midway through my own marathon multi-leg journey. Now an admission: This act of airport altruism was not an expression of saintly ambition. It was not driven by a deep concern for my harried fellow traveller. It was a test inspired by new discoveries in brain science and psychology. These insights have changed the way I travel. They may change the way you travel, too. Let me explain.

A few years ago I began following a loose-knit group of economists and psychologists who had coalesced around the same goal: to find the recipe for human happiness. They use surveys and brain scans and elaborate games to see when and why we are cheery. No matter the method, the conclusion that almost all the happiness eggheads eventually reach is that nothing – not money, not status, not roller-coaster rides or the latest smartphone – contributes to well-being as much as positive relationships with other people. When it comes to happiness, every interaction counts.

Which seems, at first, like terrible news for air travellers. The typical airport is a nexus of people who are both short of time and personal space. We're all tired, stressed and worried about making our connections, while simultaneously being pushed into close proximity with strangers. It's a perfect environment for turning fellow travellers into rivals.

Some people take refuge in the executive lounge. Others retreat from the crowd by pouring Van Halen or Thelonious Monk into their earbuds. Then there are the sprinters, who pursue airport gold by trying to beat other people to whatever line might be next. I have tried all of these methods (and so, I suspect, have you).

Paul J. Zak, director of the Center for Neuroeconomics Studies at California's Claremont Graduate University, counsels doing the opposite. Zak examines how human decisions and interactions can shape – and are shaped by – biochemical processes in the brain. His research has convinced him to see crowded airports and bumpy flights not as hardships, but opportunities for mind-altering interactions with strangers.

Illustration by Pascal Blanchet

He's even taken to orchestrating his own open-hearted moments on work trips. The guy really doesn't hold back: On a recent turboprop flight from Atlanta to Tallahassee, Zak sensed that his flight attendant, a woman in her mid-sixties on the tail end of a shift, could use a pick-me-up. He described his research to her, then offered her a big hug upon landing. She accepted. They embraced. And the entire cabin burst into applause.

That's not all that happened. In his new book, The Moral Molecule, Zak explains how, every time we interact with other people, our brains release chemicals that trigger good or bad feelings. Just as confrontations with bothersome strangers can trigger the release of stress hormones that wear us down, warmer encounters can produce the opposite effect, showering the bloodstream with a feel-good hormone called oxytocin.

Oxytocin is most commonly known as the substance that washes through women when they give birth, but Zak and his colleagues have found that just about all of us produce it whenever we engage in cooperative, trust-building encounters. It can be brought on by a hug, a handshake or even a small act of civility, such as opening a door for someone. It produces a calm feeling that enters your nervous system, slows your heart rate and actually makes you more likely to trust other people around you.

Think of the implications: When Zak hugged that flight attendant, he didn't just make her feel good; he induced a chain reaction. When she hugged him back, he got a reciprocal dose of warm and fuzzy. It is also possible that the passengers who applauded might have experienced their own hit of the feel-good hormone as they clapped. That was just the beginning. Zak's lab research shows that anyone who got the dose would be more likely to pass on favours of generosity and kindness to other people just as long as the molecule stayed in their system – which could be as long as 20 to 30 minutes. The hug effect could well have rippled out through the arrivals terminal in a series of kindnesses and stress-busting moments.

Illustration by Pascal Blanchet

"Oxytocin is an anxiety-reducer," Zak told me. "But you can't make your own brain release it – you start the cycle by reaching out to others. So when you travel, don't hide by using your iPod or laptop. Reach out!"

Zak, who is sometimes referred to as Dr. Love, lives by his research. He never misses an opportunity to hug a stranger. I got a big bear hug within moments of meeting the guy for the first time. But Zak is also living proof of the social advantage of air travel over, say, driving. I once interviewed him as he barrelled down a freeway in Southern California in his Ford Expedition. He jockeyed for position and constantly grumbled about the drivers around us. It turns out that Dr. Love is just as prone to road rage as the rest of us.

The problem, he pointed out, was communication. When we drive, we cannot see each others' eyes or the subtle signals transmitted by facial expression. We have to make do with turn signals, honks and revving engines – crude means of communication that tend to cement adversarial relationships. It's almost impossible to build a sense of empathy with other drivers, especially when moving at freeway speeds. Which is why the typical freeway is a cauldron of mistrust and competition.

But when we walk or cycle – or fly, for that matter – the sensory veil is removed: We can see and hear and touch and help one another, and in these realms find a thousand opportunities to build trust, cooperate and express our good selves.

Illustration by Pascal Blanchet

This doesn't mean we all need to go off hugging people, or chasing down tragic cases in need of help with their luggage. "You can get a little mood boost in the middle of a stressful travel experience just by talking to a stranger," Elizabeth Dunn, a professor of psychology at the University of British Columbia and author of the forthcoming book Happy Money, told me. In fact, in laboratory experiments, Dunn found that talking to complete strangers for a few minutes gave people about the same happiness boost as chatting with their significant others. That's because most of us unconsciously perk up and put on our best face the moment we interact with those we don't know. The performance shift actually cheers us up.

This is the happy message contained in the research: Not only are we soft-wired to be nice to other people, our brains reward us for it.

Yes, air travel can be stressful. Yes, it involves some persistent uncertainties – you cannot guarantee that your flight will leave on time or that you will enjoy the kind of pristine isolation you do in your car. But if you embrace the altruistic opportunities presented by proximity, if you reach out, the air travel environment offers transcendent possibility. Journeys among strangers are more than ordeals to be endured. They are a chance to be our best selves. 

Fortunately, the journey – and your own brain – can be altered by even the smallest act of civility. If you are tired and frustrated and miles from home and you see me in the bag check line, I dare you: Smile. I promise I'll pass it on. 

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