The editor who gave me my first job in Australia as an (ahem) seasoned reporter saw many advantages in having older employees.

We've been round the houses and know how many beans make five.

We don't generally come with all the emotional baggage of people in their teens and twenties - all that Monday morning "I can't believe I did that when I was drunk/my flatmate stole my milk from the fridge" stuff.

My old boss didn't need to know about the burning question of his child employees' day: "Should I buy a puppy?" The flatmate's fish had died but it wasn't murder so move on.

What we more mature workers do is come into the office, roll up our sleeves and get on with it - wisely. We read and think and work. Wisely.

The facts are with us. Churchill became prime minister when he was 65. Verdi wrote his great opera Falstaff in his late 70s and it fizzes with life and laughter.

Warren Buffett remains the world's shrewdest investor at the age of 89. His business partner, Charlie Munger, is 96.

Ronald Reagan put it best when he faced a much younger Walter Mondale in a presidential debate in 1984. Would Reagan's ancientness disqualify him?

"I will not make age an issue of this campaign. I am not going to exploit, for political purposes, my opponent's youth and inexperience."

And he was right. Young and old bring different strengths and weaknesses. Physical ability to knock a million doors a day? Give it to the youngster in the corner. Wild horses won't hold her back.

A bit of thought and wisdom? Turn to someone older.

But it's not the way it works. Ageism may be the last ism that isn't a was-ism.

Make a racist or a sexist remark in work and you'll find yourself in front of a human resources manager faster than you can say "sacked", even if the Twitter mob don't get you first.

Facebook's founder Mark Zuckerberg once said (at the age of 22) "young people are just smarter". Imagine the row if he had said "white people are just smarter" or "men are just smarter".

Just take a look at the parade of young people presenting the television news shows, immaculately groomed, with bright smiles through nice white teeth. Long in the tooth, they are not.

A television producer once told me that presenters had to be "easy on the eye". To my mind, "easy on the brain" would have been better.

Research by the University of Melbourne found widespread ageism in Australia. Young people believe the economic falsehood that old people take their jobs. They don't. That's called the "lump of labour fallacy", the misconception that there's only a fixed amount of work to go round - debunked but widely believed.

And the Melbourne research showed widespread belief in false stereotypes.

It's true we do get physically slower as we age - but mentally, the slowing isn't as fast as you might think.

The American neuroscientist Daniel J. Levitin wrote that long-term memory is not impaired much as we age. Old people remember their classmates from primary school six and more decades later.

Short term memory - what you went into the kitchen to get - declines slightly with age but not that much. It's more that older people worry about an incident of forgetfulness. They also have more memory to filter - more people met so a longer pause before remembering a name.

As Dr Levitin puts it: "The relevant difference is not age but rather how we describe these events, the stories we tell ourselves about them.

"Twenty-year-olds don't think, 'Oh dear, this must be early-onset Alzheimer's.' They think, 'I've got a lot on my plate right now' or 'I really need to get more than four hours of sleep.'

"The 70-year-old observes these same events and worries about her brain health."

Another myth is that the young are the most enterprising. Research in the United States showed that the average founder of the fastest growing tech companies was 45 years of age when he or she set up the enterprise. Success was nearly twice as likely for a 50-year-old entrepreneur as it was for a 30-year-old.

So when that twenty-something comes in with his backward-facing baseball cap and puts his sneakers on your desk seeking money for a whizzo venture that just can't go wrong, dude, don't do it.

Clutch your wallet. Wait for a wise old head to appear around the door - ideally Warren Buffett's.

Some things do fade with age - perhaps the thrill of the new. Will we ever get quite the same joy again as we did when we first smelt eucalyptus or a baby?

But enthusiasm comes at all ages. Curiosity and the joy of discovery are not confined to the young. I have known people who, I swear, were born bored and people who were curious until the very day they died.

Some things improve with age. Mature love is better than mad teenage love. First fumbled sex only gets better. (By they way, young people didn't invent sex. They think they did but they didn't.)

The point is - as it is with racism or sexism - judge people on ability rather than by age (or gender or skin colour or sexual orientation or the shape of their eyes or where they pray or don't pray).

Australia needs every ounce of wisdom.