'Congratulations on owning a new iPhone 6!' Right then, a gushing'congratulations' from the Apple call centre was the last thing I wanted to hear. With my beautiful new phone reduced to a sorry spider's web of cracked and splintered glass, forget congratulations - I wanted commiserations.

And then I wanted answers. Could they mend it? Would rumours that it warranted a brand new replacement costing over £250 turn out to be true? How long would it take? And I wanted a response, please, in rather less than the 20 minutes already spent being shifted around Apple support's robot algorithms.

And yet... as the conversation progressed I realised that the word 'congratulations' had worked a strange magic. At a stroke, it seemed, Apple's scripted exercise in brand awareness had deflated my frustration, reframed my perspective, and subverted my ego-absorption. I felt different. Overwhelmed by the small disappointment of a cracked screen (it turned out that it could easily be replaced) I'd forgotten that I was blessed to be among the top few percent of the world's population for wealth and prosperity. Be thankful. OK, it was going to hurt my wallet to fix my new phone, as only Apple knows how, but I could afford it. It was my pride and need for control that was being hurt, not my wallet.

Thanks for nothing?

This trivial incident is a powerful reminder of the ways of the fallen heart and the medicine it needs. Shower us with the brightest and the best and were main self-absorbed, discontented, ungrateful souls. As Bart Simpson (from the irreverent US TV animation The Simpsons) would say before supper: 'Dear God, we paid for all this stuff ourselves so thanks for nothing'.

By contrast, the Bible presents the cultivation of gratitude as one of the core disciplines of the Christian life. 'Overflowing' with gratitude, we are called to give thanks 'always' and for 'everything' 1 in 'whatever [we] do'. 2 We are called to be grateful because it is the right thing to do: a spirit of thankfulness acknowledges the sovereignty of God and asserts the dependency of his creatures. It positions grace at the very centre of our spiritual journey.

Healthy gratitude

But it turns out that cultivating a grateful spirit is a good thing to do as well. Psychologists are beginning to uncover how cultivating gratitude benefits mental health and wellbeing. 3 This must never be our primary motivation, of course, but these developments should encourage us on our journey. Here's how it works.

Nuts and bolts

First, gratitude changes our psychological posture. Like physical posture, our psychological posture (or mindset) is the way we incline toward the world. It determines what we see and how we see it. Gratitude forces us to shift posture because it is a powerful subverter of the control, autonomy and entitlement that sits so naturally with the fallen mind.

Being thankful creates a state of psychological dissonance. You cannot cede control in gratitude whilst at the same moment grasping onto it. You cannot recognise the gracious act of the giver whilst asserting your entitlement to their gift. It's one or the other - you cannot have both. The act of saying'thank you' dispels pride and entitlement, instead nudging us toward the virtues of humility, dependence and submission.

Second, gratitude appears to exert a positive effect on mood and general wellbeing. For example, in one of his studies in this area, the psychologist Robert Emmons randomised subjects to one of three journaling tasks. 4 Those in the first group were instructed to keep a record of the events and circumstances of the day for which they were grateful and then to meditate thankfully by 'counting their blessings'; the second kept a record of 'hassles of the day'; and the third a list of neutral events. When Emmons compared the outcomes across a range of mental health indicators several weeks later, the gratitude group scored significantly higher in several sectors, reporting a more positive and optimistic mood overall.

Let's be clear, learning to cultivate gratitude in this way isn't a cure-all and it is unlikely to make much impression on entrenched depression. We don't know how well benefits are sustained over the longer term. And it is probably better to start to practise the discipline of gratitude in this way when life is going well, rather than in the depths of despair or when confronting trauma and loss. This is a liturgy that needs to be cultivated gradually, day by day, month my month, year after year: patiently reconstructing a psychological posture of thankfulness.

But what might a regular liturgy of contemplative gratitude look like? It starts first with the decision,let's say for ten minutes every day, to inhabit the present moment. Gratitude wrenches us out of the future, with its endless planning, and forces us back into the present. Put down the iPhone, close the calendar, put aside the 'to-do' list and pause in God's presence.

Second, think intentionally about what is good: about God, the gospel and about your life circumstances right now. Literally counting our blessings in this way imposes a positive cognitive filter on our relationship with the world, forcing us to go looking, intentionally, for what is good. It summons us to locate, and then to contemplate, the 'ten thousand places' where we happen upon the grace of Christ every day of our lives.

GK Chesterton, for example, revelled in the goodness that he discovered dancing everywhere around him:
'I like the cyclostyle ink, it is so inky. I do not think there is anyone who takes such fierce pleasure in things being themselves as I do. The startling wetness of water excites me; the fieriness of fire, the steeliness of steel, the unutterable muddiness of mud...'

The language of gratitude forces us to slow into the present moment, to discern what is true, what is noble, what is right, pure, lovely, admirable - and then to notice them.5

Third, and finally, offer words of thanks to God as the author and giver of all that is good. Take moments to imagine his gracious face, his open, bountiful nature, and his self-giving posture of generosity. Affirm the gifts around you as tangible evidence of his goodness - see them, touch them, savour them. Say thank you over and over, moving back and forth between the gift and the giver.

Achievement?

A posture of thankfulness should not undermine a sense of personal achievement built upon our efforts and determination. When the fruits of our labour have blessed others, and brought life to the world, we should stand ready to receive their gratitude as well as praise from God himself.

But then pause to remember the grace-drenched context of your achievements - you did it in his strength, drawing on his encouragement and inspiration,motivated by his pleasure and delight. You probably used the fruits of other people's labour too - the Chinese technician who assembled the keyboard on which you write, the Brazilian sailor who manned the container ship that carried it across oceans, the Polish van driver who knocked on your door. Give thanks for them and for their labour. Position your efforts in the context of the sovereignty of God - for what do you have (your skills, aptitudes, even your dogged determination) that you did not in some sense also receive? 6

Training the heart

That's it. Ten minutes a day is a long time for an ungrateful heart. But if we want to train the heart to aim well, to default in the midst of life's challenges with a godly spirit of thankfulness, here is a liturgy that is right and good. Good for you, good for others and good for the life of the world. And as an added bonus, after a few years, the ink may begin to appear a little, well, inkier.

Glynn Harrison is Emeritus Professor of Psychiatry at the University of Bristol.

Two examples of practical gratitude

• When I asked some Middle Eastern doctors how they'd slept, they replied, 'Well thanks, by the grace of God!' I am more likely to imagine that good sleep is a result of my metabolism, genes or occasional discipline in getting to bed early. But the Bible encourages us to celebrate God's provision and grace, even in such small things. 7 It's certainly a more affirmative start to the day!

• The doctors clubbed together to buy our operations team small gifts at Christmas. We were embarrassed by expressions of how much it meant to them. Medical staff gets lots of appreciation and praise. In contrast the back room staff are often overlooked and invisible. Without their tireless efforts in chasing and expediting the thankless tasks, the NHS would grind to a halt. There are examples in the Bible of our heavenly father taking care to remember the names of faithful workers such as the Hebrew midwives in Exodus, Shiphrah and Puah. 8 We all like to be remembered with an occasional thank you.

Alex Bunn