Last night, my family and I had dinner with an old friend.

I should clarify … by ‘old’, I don’t mean ‘geriatric’. I mean that I have known this friend for a long time. She is the person I have been friends with the longest, having first met her in early medical school nearly a quarter of a century ago. It’s a friendship that survives despite geographical, logistical and theological differences, because it’s built on the deepest mutual respect and care. I don’t have many friends, but this friend is definitely a keeper.

Friendships mean different things to different people. Some friends are gregarious, a source of instant joy, that person that always makes you laugh even when life makes you want to cry. Then there are those friends who enkindle that deeper sense of joy, because they are steadfast through the tough times.

In the 21st century, our concept of friendship has undergone some pretty radical changes. Before 2004, ‘social networks’ were the people you physically hung out with. Now when you talk about ‘social networks’, people assume you’re referring to Facebook.

Is physical social networking better than virtual? Everyone has their own opinion. We know that humans are wired for social interaction, with specific areas of the brain devoted to social behaviour, such as the orbitofrontal cortex. There are also neurotransmitters and hormones that are strongly associated with bonding and maintenance of social relationships, like oxytocin and β-endorphins. Research has shown that both humans and other primates find social stimuli intrinsically rewarding—babies look longer at faces than at non-face stimuli.

We also know that people who engage in social relationships are more likely to live longer, and that loneliness predicts depressive symptoms, impaired sleep and daytime dysfunction, reductions in physical activity, and impaired mental health and cognition. At the biological level, loneliness is associated with altered blood pressure, increased stress hormone secretion, a shift in the balance of cytokines towards inflammation and altered immunity. Loneliness may predict a shortened life-span.

It’s important to understand what loneliness is, and conversely, what defines good social relationships? Fundamentally, good or bad social relationships are related to the quality of the social interaction. This rule applies equally to real social networks and their on-line equivalents. So quality is fundamentally more important than quantity in terms of friendships, with that quality strongly determined by the connection within those social relationships. For example, loneliness “can be thought of as perceived isolation and is more accurately defined as the distressing feeling that accompanies discrepancies between one’s desired and actual social relationships”.

The corollary is that friendship can be thought of as perceived connection within social relationships, or the comforting feeling that accompanies the match between one’s desired and actual social relationships.

So healthy social relationships aren’t defined by the size of your network, but by the strength of the connections that your network contains, relative to what’s important to you. Just because you’re not a vivacious extrovert who is friends with everyone doesn’t mean that your social network is lacking. It also means that you can have meaningful connections to friends through social media, just as much as you can have meaningful connections through face-to-face interactions. It’s not the way you interact, but the quality of the connection that counts.

One way to increase the quality of your social connections is to enjoy your friendships mindfully. Mindfulness is being fully engaged in the present moment. So mindful friendships is to be fully engaged with the other people around you, to use all your senses to connect with those around you. To ignore the other social networks around you on your phone or tablet, keeping them out of sight and out of mind until afterwards.

Try it. At the next Christmas party, or when you’re with your loved ones on Christmas Day, turn off the phone and engage with the people around you as mindfully as you can, and see if you experience a new and improved form of Christmas joy.