It was good news in a bad year: Back in 2009, the United Nations Food and Agriculture Office (FAO) announced that the number of chronically undernourished people in the world, which had been falling fairly steadily since 1995, was expected to plummet by almost 10 per cent in the next two years. Tens of millions would be saved from hunger.

But this week, the FAO acknowledged it had been wrong. Hunger hadn't declined. It had increased. In fact, hunger has been growing for more than two decades. It is now 13 per cent higher than it was in 1990.

Now, let me ask you two questions: How big is this news? And how bad?

I suspect you will say, "it's a huge story. And it's horrible. Absolutely tragic. It should be on the front page of every newspaper in the world."

So now I'll tell you that what I wrote above isn't true. In fact, it's the opposite of the truth.

In 2009, the FAO said a long-term rise in global hunger would spike over the coming two years, leaving one billion people or more without enough to eat. This week, the FAO said that was wrong. After careful examination of its data and methodologies, the FAO issued new statistics that show hunger has been falling slowly and steadily for more than two decades. There are now 13 per cent fewer hungry people in the world than there were in 1990. And there was no increase in chronic undernourishment following the food crisis of 2008.

Now let me ask you two questions: How big is this news? And how good?

Logically, this news should be as big if the data had been revised in the other direction, and as good as the alternative would be bad. And it should be on the front page of every newspaper in the world.

But it wasn't. The FAO's revised figures were widely reported but only in small stories deep inside newspapers, and many of those stories downplayed the revisions as some sort of arcane statistical matter that shouldn't obscure the awfulness of global hunger. It was a sharp contrast with 2009, when the FAO's gloomy statistics were a huge story all over the world.

For anyone who follows the media carefully, none of this was surprising. One of the most basic biases in news reporting is the media's preference for woe and despair. "Good news" is very close to an oxymoron.

The standard explanation for this tendency is sensationalism - "if it bleeds, it leads" - but that's incomplete. It may even be the least important of the factors at work.

It's not just journalists who focus on the negative. Everyone does. Psychologists call it "negativity bias."

It's also very human to be drawn to information presented in the form of a story, which means dropping the numbers in favour of individual, identifiable people. That's easily done when statistics show an increase in something bad, like hunger. You just write the gripping story of a hungry child. But when the statistics show an improvement? The story of a child who isn't hungry is a boring story.

There are also social pressures at work. Emphasize that something horrible like hunger has diminished and you may come off looking callous. There's also a risk that you will sound complacent, or that you will actually promote complacency.

You can see those fears at work in the FAO's handling of its revised data.

On the FAO website, the link to the report is a striking graphic of seven silhouettes in white and one in blood red. Above, in large font, is "1/8" with the "1" again in red. Of course, "one in eight" is the number of people undernourished people in the world. Only when you click on the link and get into the text of the press release do you learn that "progress in reducing hunger during the past 20 years has been better than previously believed" - which is immediately followed by a warning that "the number of people suffering from chronic undernourishment is still unacceptably high, and eradication of hunger remains a major global challenge."

Most newspaper reports followed this lead: There was grudging acknowledgment of good news but a heavy emphasis on how many people still don't get enough to eat.

This sensitivity is understandable. Even laudable. But it ignores a critical point.

If people constantly hear news of war, disaster, crime, disease, poverty, misery and sorrow, they will not unreasonably conclude that the world is a nasty place getting worse all the time. And they will have a very hard time believing evidence to the contrary.

I've seen this dynamic personally. In my books and columns, I've discussed at great length how progress over years, decades, and centuries has made us the safest, healthiest and wealthiest people who ever lived. The evidence is overwhelming. It could fill a library. And many people absolutely refuse to believe it. They are quite certain the world is a nasty place getting worse all the time, statistics be damned.

And they don't think it can get better.

That's what well-intentioned people who emphasize bad news don't understand. If people believe that things only get worse, they will not leap up and get to work making them better. They will lie down on the couch and watch the world go to hell on TV.

Only if people believe that progress is possible will they demand that governments deliver it and pitch in to make it happen.

So, yes, it's important to note that one in eight people are hungry. But it's equally important to tell people that humanity has made real, long-term, sustained progress in reducing that number - because that is the proof that so much more can be done.