Be it a brief squeeze or a bone-crushing bear hug, few can deny the comfort of a farewell cuddle from a person you love. Yet in an effort to keep traffic flowing at Dunedin international airport on New Zealand's South Island, bosses have decided to impose a three-minute cap on hugging in the airport's drop-off zone.
Passengers wishing to engage in longer and fonder farewells have been instructed to use the car park instead.
In contrast, Heathrow has told passengers to take as much time as they need saying goodbye to loved ones in departures.
New signage in the airport's departures area shows two people hugging, with the words "Max hug time, unlimited. Fond farewells in departures, encouraged".
This is fortunate, because hugging bestows an array of physical and psychological benefits, experts say.
Humans are not the only creature to indulge in hug-like behaviour; many monkeys and apes comb through each other's fur, and it is likely that human hugging has evolved as an extension of this. "The basic method of social bonding for creating relationships is through physical touch," says Prof Robin Dunbar, an evolutionary psychologist at the University of Oxford and author of The Social Brain.
"What's going on below the surface is the triggering of a highly specialised neural system in the skin that responds to a very specific stimulation - light, slow stroking at a rate of 3cm per second, which is the speed of sweeping hand movements through the fur, or across the skin - and it triggers the endorphin system in the brain, which makes you feel calm and relaxed."
Related: New Zealand airport causes stir with sign capping goodbye cuddles to 3 minutes
While the release of endorphins helps to build and maintain close relationships, the benefits of hugging also extend to other areas of health and wellness.
"Many of us know that it feels good to receive a hug, but we don't often stop and think about the other positive effects of hugging," says Prof Michael Banissy, a social neuroscientist at the University of Bristol and the author of When We Touch.
For starters, hugs can affect our immune responses. In one study, researchers at Carnegie Mellon University in the US found a correlation between how often people experienced hugs, and their ability to fight off colds. Those who received regular hugs in the 14 days before being exposed to a common cold virus were less likely to become infected, and experienced fewer severe symptoms if they did, compared with non-huggers.
Another study found that women who embraced their partner before undergoing a stressful experience had a lower biological stress response, as measured through levels of the stress hormone cortisol, compared with those who didn't receive a hug.
"In the context of going to an airport and taking a flight, you can see how hugs could play out as beneficial in terms of managing people's anxiety or stress levels," says Banissy. "The three-minute thing is interesting, because technically, the hormones that play a role in modulating these effects can be released within a few minutes, so that could be enough to get the benefit."
Banissy adds:"On the flip side, we know that touch and hugs are very much influenced by context; touch needs to be wanted and feel appropriate, so you might imagine that if hugging feels unnatural for any reason, you're not going to get the same level of benefit. There's a bit of a risk with putting a time cap on it, that people might feel a bit tense about it - although I'm told they're not going to have hug police."
The most common type of hug is what psychologists refer to as a "crisscross hug", where the huggers' arms are crossed over one another's shoulders and waists. The duration matters. Although some people may prefer a slightly longer or a shorter hug, when Banissy and his colleagues at the University of Bristol studied how pleasant and under control hugs lasting one, five or 10 seconds felt, they found that one-second hugs were consistently rated the least enjoyable. "If it's too brief, people may not necessarily feel the benefits in terms of emotional closeness and things like that, but equally, if it's too long it can start to feel uncomfortable," says Banissy. "Five to ten seconds appears to be optimal."
Engulfing hug
When you're feeling down or have received some terrible news, an engulfing hug can provide comfort and emotional support. "It tends to be restricted to emotive scenarios, as it may feel too intimate in other settings," says Banissy. "It is where someone literally wraps their arms around you and effectively engulfs you, bringing you in really close."
Bear hug
Whereas the engulfing hug typically draws the recipient in from the back, the bear hug is more of a random grab and tight squeeze. The purpose and the emotion behind the hug also differs: "Bear hugs are often a celebratory thing, like a family reunion, or recognising an accomplishment of some kind, whereas the engulfing hug is much more supportive and tender," says Banissy.
Sporty shoulder press
Physical gestures are a common feature of team sports, including the sideways semi-hug, semi-shoulder bump. Although the cynical might read this as an attempt to avoid contamination with the other person's sweat, research suggest these positive physical gestures still matter. Banissy says: "If you look at how often team members engage in positive touches, which includes hugs, but also things like fist bumps and high fives, you find that teams that do this more often early in the season often then go on to win more games. There's kind of a link with this and their team cohesion."
Global leader hug
Hugging in professional settings can feel awkward, perhaps even more so when the world is watching and scrutinising your intent. So, no wonder politicians look so uncomfortable when they do it. Although there is scant research on how hugs affect professional transactions, "we do know that other forms of touch in professional settings set the stage for things like cooperation and trust", says Banissy. "For instance, people who perform more handshakes before negotiating business deals are more likely to come to joint agreements, or find outcomes that are mutually beneficial. Touch plays a really important role in that space."
Dunbar says we should consider hugs as opening bids to establish the nature of relationships, and just do what feels natural or instinctive. "There are bound to be mistakes where we overbid or underbid relative to the other person, but my advice is to switch the brain off and let the body take over."
Self-hug
Receiving a hug before a stressful event can help to mitigate its emotional impact, but what if you don't have anyone to hug? Fortunately, research suggests that placing your own hands over your heart or belly, or stroking the skin of your upper arms, appears to have a similar effect.
When scientists at Goethe University in Germany compared the impact of these self-soothing gestures with receiving a hug from someone else, they found that both groups released lower amounts of the stress hormone cortisol in response to a stressful situation, compared with a control group.