In 2006, when the economy was at full throttle, powering inexorably towards a cliff that had yet to loom into view, the annual Gallup survey of national wellbeing placed Irish people in eighth place on its global index. Seventy per cent of Irish people told the pollster they were thriving. On a scale of one to 10, they ranked their future prospects at eight.

When Gallup returned to the field four years later, in 2010, the wreckage of the crash was strewn everywhere. The government was slowly falling apart. If there was a nadir, that was probably it. Yet the pollster came up with some surprising numbers.

By 2010, Ireland had moved from eighth place to tenth on the optimism table. Some 56 per cent of people described themselves as thriving – just 14 points lower than in 2006. More said they were struggling, but the optimism figures were still higher than in the US, the UK or Germany.

Was it fatalism? "No, I think we're dispositionally optimistic," says Maureen Gaffney, adjunct professor of psychology and society in UCD and the author of the best-selling Flourishing. "We don't have American-style optimism. I think the Irish one is captured by the word 'grand'. It's kind of ambiguous. It's not setting the bar too high, and it's also not committing yourself. That actually is what keeps us going."

When pollsters ask Irish people about their satisfaction with their home life, their community and their own prospects, the results tend to be quite even or positive. But ask them to rate their confidence in institutions, in the direction of the country or its future prospects, and the figures go through the floor. Gaffney, who published her book in 2011 and spends much of her time speaking to organisations and communities around the country, says this public/private paradox has been clearly in evidence throughout the economic crisis of recent years.

Onslaught of negativity "The first question I was asked at virtually every forum I talked at was, 'What can we do to protect ourselves from the onslaught of negativity?' People felt overwhelmed by it," she says. "I think people felt, how can I keep myself going. People were suffering – some far more than others. But wherever you were on the suffering spectrum, you still were faced with the job of keeping yourself going."

Gaffney believes this explains why her book resonated with so many people. Flourishing, which is the basis for a new television series that begins this week, synthesises a great deal of the psychological research on happiness and optimism and uses it to set out practical steps that help people achieve a deeper sense of well-being and meaning. Making use of the insights of neurology, for example, Gaffney explains the negativity bias – the greater power of negative feelings and thoughts over the positive in virtually every arena of human functioning – and suggests ways to offset it.

Gaffney dates the negativity bias to the Enlightenment, when the Christian view represented by St Augustine and Thomas Aquinas – happiness is a non-runner in this life, but play your cards right and you’ll have it in the next – was challenged by the focus on the individual, his dignity and agency. Until this century, she argues, psychology was preoccupied with why things go wrong: why marriages end, why children don’t develop as they should, why we get depressed. Around 2000, there was a “sea change” in the field, an explosion of research on the flip-side of human behaviour: how people survive terrible traumas, how marriages endure, how people come through difficult childhoods.

Gaffney’s insights are aimed at the individual, but she believes they’re directly applicable to organisations and societies as well. “Organisational values such as compassion, gratitude, forgiveness, internal trust and optimism may seem remote from profitability, productivity, quality, customer retention,” she writes. “Yet studies of organisations across a number of sectors have shown that those which score higher on such values perform significantly better than other organisations on precisely those practical things.”

In one study cited by Gaffney, two groups of doctors were invited to a laboratory and told they were to sit a test of their diagnostic skills. Both were given a portfolio of cases, including clinical signs and symptoms and case histories, and were asked to make a diagnosis and recommendations for treatment. One of the groups was given a thank-you note and eight sweets; the other wasn’t.

“What they found was that the doctors who were given the thank-you note and the token of appreciation made accurate diagnoses faster, were more interested in the patient and made a lot more recommendations,” Gaffney says. “They were very invested in thinking of other things they could do to help this patient.”

But what about negative energy? Is there not a danger of dulling the anger and passion that drives people to protest or agitate or argue for better societies? Not so, Gaffney responds. “Your brain is wired. All the evidence is that the negative has a stronger grip on you than the positive. That’s ineradicable.”

Gullibility is a different thing, she says. “If you go out and it’s lashing rain and the clouds are backed up and you say, it’s going to be a sunny day, you’re not being optimistic; you’re being gullible or engaging in wishful thinking.”

Gaffney makes a persuasive argument for optimism, but has it necessarily made the best case for itself? In a recent critique of America's "positive thinking" industry, the writer and political activist Barbara Ehrenreich argues that the same "frothy wave of mandatory optimism" that spread across corporate culture eventually swept through the once-sober finance industry, with calamitous results. Bankers deluded themselves.

"No one was psychologically prepared for hard times, when they hit, because, according to the tenets of positive thinking, even to think of trouble is to bring it on," Ehrenreich writes. "If you live in a bubble of perfect wish-fulfilment, how could you imagine that, for example, some poor fellow in Cleveland might run up against unexpected medical bills or car problems that could waylay his mortgage payments?"

Deluded optimism Gaffney draws a distinction. "There's a tendency, particularly in America, where optimism becomes an ideology, almost. Not only must you stay optimistic if you just got a devastating diagnosis of cancer, but you must almost go around saying, I'm glad it happened to me."

Moreover, she disagrees that deluded optimism lay at the root of Ireland’s boom and bust. “It wasn’t optimism. It was mania combined with anxiety . . . An awful lot of ordinary people were actually driven by anxiety. They were thinking, my kids are never going to get on the housing ladder.

“Optimism, as it’s defined by researchers and psychologists, is a realistic optimism . . . It’s believing that in the long run things are going to work out if you make an effort and if you persist, and without any guarantees. There is no known evidence, psychologically, that it’s ever a bad strategy.”

How to Be Happy is on RTÉ One on Tuesday