Yvonne Roberts: The age of the aged has at long last arrived

A growing mountain of research tells us that many people get happier as they age

So vintage still packs plenty of va-va-voom! Novelist PD James, 90 on her next birthday, is applauded for the way in which on Radio Four's Today programme, she neatly and very courteously filleted the hapless Mark Thompson, director-general of the BBC, for – among other issues – running a public service institution that appears to lack a moral core.

Somehow, an extra layer of gravitas added to the charges precisely because they were delivered by a woman of integrity who has lived a life – work, wars, marriage, love, loss and survival – and who clearly cares about what becomes of this society. Who wouldn't esteem the scope of that experience?

Well, quite a lot of us it seems. But since now is probably the best opportunity this decade for optimism to flower, why not hope that, with such a cracking start, this will be the era that puts ageism on the run? And places a higher value on weathered wit and wisdom?

Certainly, statistics tell us that ahead lies a similar age-quake to that which hit the 1960s. Then, for the first time, young people – often with cash in their pockets and that rare commodity, genuine prospects – became a majority in the population. Now, they are growing old. The number of pensioners in the UK is set to soar to 16 million by 2050 while more than 280,000 will be centenarians – compared with 10,000 today.

Pessimism is the familiar context in which the advent of an ageing population is discussed – and that in itself feeds ageism. Pessimism points to pensioner poverty and the failure to tackle who pays what for those who need institutional care. (And to ask why so many of those suffering from dementia are warehoused, without stimulation and compassion.) But shake the kaleidoscope and more positive patterns appear – paradoxically, many to do with ageing and happiness and wellbeing.

Cue Edwin Shackleton, aged 82 and the American thirty-something writer, Gretchen Rubin. Last year, Edwin challenged himself to use 100 different modes of transport in 12 months. He beat his own record. He has experienced 136 ways to travel, including a lifeboat, a gypsy caravan, a hot air balloon, a glider and a T-55 tank. "I've always been a bit of thrill seeker," Mr Shackleton explains. "It's all been such fun. People have been so kind."

Mr Shackleton is a retired engineer, a widower, and he intends to continue to collect new modes of transport including a sedan chair and a hydrofoil. Why? Because he's of an age when he can. Is Mr Shackleton active? Connected? Giving something back? All elements that, according to the New Economics Foundation think tank, contribute to wellbeing. Yes, yes and yes. But Mr Shackleton probably doesn't have time for such levels of introspection – he's too busy organising his next lift.

Contrast this approach with that of Ms Rubin's. And you have a glimpse of the growing chasm between young and old and the theory and practice of happiness. Her book The Happiness Project chronicles the year she spent "test-driving the wisdom of the ages". She says she has used herself as a guinea pig to apply various theories about how to be happier. She now wants to start a movement – so you too can apply her happiness tool kit; subscribe to her newsletter; read her blog and abide by her counter-intuitive commands on how to achieve happiness. These include – do buy happiness; do let the sun go down on anger; don't practice random acts of kindness; focus on being nice to those whom you think won't be offended by your largesse. And "fake it till you feel it". Act happy and you might become happy.

Somewhere buried deep in all this mechanistic rag bag are nuggets of obvious good sense – "To be happy we need to feel loved, secure, good at what we do and have a sense of control". But, as so many of those in their eighties and nineties will tell you, that can't be achieved easily via a book, or a blog. When life gets in the way – economic depression, world war, death, illness – what really helps is a bit of sagacity; a sense of who you are and the acquisition of a set of values; precisely the sub-plot of Baroness James's interrogation.

I'm sure Ms Rubin means well (she's certainly making her bank manager happier) but can happiness and wellbeing really be self taught? Cognitive behaviour therapy, for some, can help to calibrate more destructive thoughts. Thinking positively can undoubtedly make life easier. But what a growing mountain of research says is that with or without this homework, many people get happier as they age.

They develop a sense of perspective; they don't waste time or money on what doesn't matter and they place a premium on the people and relationships who count in their lives. But how can those who are younger – and much more concerned with isolation and loneliness – learn the benefit of these essentially anti-individualist, anti-competitive, anti-consumerist attitudes, so long happiness is seen as a Gucci handbag, a mountain of debt and 150 "friends" on Facebook?

The coming grey wave might just ensure that those who have been discriminated against and seen but not heard will begin find their voice. And the young might even listen.