Often, it seems, nostalgia has no quality control. So what's it all about? Why do some people flock to reunions and go on drunken-download benders and not others?

Frederick Barrett is Assistant Professor of Psychiatry and Behavioral Sciences at Johns Hopkins University in the United States. A study by his team in 2016 found some people are more susceptible to nostalgia. Weirdly, when those people listen to music from their teenage years, the areas of their midbrain involved in reward are less active than in people who aren't so prone to nostalgia. It seems contradictory, but Barrett says, "it may be that those who do not experience it as often find more reward when they do. The more often a stimulus is encountered, the less rewarding it may be." But that doesn't stop us trying again and again.

As a neuroscientist, Barrett is intrigued by the topic. "There are a number of theories of emotions that imply that you can only experience one emotion at a time. Yet nostalgia is a bittersweet longing for something you don't have any more. It's the quintessential mixed emotion."

A 2010 study by Barrett and his team found that nostalgia could be framed as either a sad or joyful experience depending on the individual. The test group filled in a battery of personality metrics and people who were further up the "sadness" personality scale reported experiencing fewer positive emotions when played music. For them, it's more a wallow than a revelry.

Other neuroscientists agree that we shouldn't underestimate the power of nostalgia. A 2007 Japanese study found that it instilled a sense of self worth and a desire to live in older adults who participate in reminiscence therapy. And researchers at the University of Southampton argue that while once nostalgia was indeed seen as a psychiatric disorder, it's increasing viewed as a pro-social behaviour, fostering continuity between past and present and increasing meaning in life.

Former Countdown voiceover artist Gavin Wood – now back on our screens in Classic Countdown – is one person for whom nostalgia falls on the side of joy. "To go back to where you feel most comfortable is a wonderful form of daydreaming," he says, citing a childhood spent watching Uptight and Happening 70. He says most Countdown fans come up to him wanting to talk about the impact the show had on them.

He reckons golden-oldie radio programs underestimate fans. "I worked for a few stations and when the Beatles albums came out we played them so much we had to buy new copies – but we only played two or three hits from each. I guarantee every other track would have been just as well received."

Steve Harnell would agree with that. He's editor of the Classic Popmagazine, based in the UK for a global audience hungry for the nitty-gritty details they weren't given first time around, or were too young to appreciate. Want to read about Alannah Currie from The Thompson Twins storming Parliament in New Zealand in her bra as an anti-GM activist? No problem.

"We're telling stories that have been left untold," Harnell says. "There are great interviewees out there from the '80s who haven't had a chance to be dealt with in a serious manner by the press. We delve into their 'pomp' years but also what they're up to now. Thankfully, this year has seen a mass of what you might call heritage acts returning with great albums, not least Depeche Mode, Alison Moyet and Nick Heyward."

One person who bristles at the term "heritage" is Day on the Green's Michael Newton. Since 2001 he's been putting on shows of legendary artists, often in the form of irresistible double bills: Cyndi Lauper/Blondie, Simple Minds/B52s, Paul Simon/Sting and the forthcoming Stevie Nicks/Pretenders and '90s rock extravaganza with The Living End, Spiderbait, Veruca Salt and others.

"I get a bit aggrieved that 'heritage' is kind of a dirty word,' he says. "Does it mean 'seen better days'? A lot of older acts have been copied, re-interpreted and are massive influences on current artists. Sticky Fingers would love to be The Stones. Violent Soho sound like Nirvana. You can hear The Faces in You Am I."

He concedes that older acts have to play their hits when they tour – "that's what customers pay to hear" – but adds that, like Blondie this year, they're often releasing quality new material. "However, with the classic hits format at radio, most new records by older acts would not get played, which is a shame."

You'll see entire families at a Day on the Green concert, which wouldn't surprise Karen Freedman – she'll regularly pull younger family members into her nostalgia orbit. Freedman was 12 years old in 1981, when she first got into a filming of Countdown at the Elsternwick studios. She'd just turned up and chanced her arm, and from that point on the crew let her in every time. She wound up being a veteran of more than 200 shows.

Barrett has explained that proneness to experiencing nostalgia is a personality trait, so how does Freedman view her personality? "I like things how I like them. I've still got lots of friends from my childhood and I'm very loyal; that's why my favourite bands 30 years ago are my favourite bands now. A friend tells me I don't support the industry, but I do because I buy every single thing my favourite artists have done in every format … apart from downloads, which are just air."

Is there not sometimes a morbid curiosity in catching a band 30 years on? "Yes, and also 'spot the original member'. We saw Boney M years ago and it certainly wasn't the original, but it didn't matter because it sounded the same. I like to see proper musicianship. Seeing Queen with Adam Lambert was fantastic – I was right at the front with my nephew, it was his first gig. I told him not to get used to this – it won't be this good all the time."

It's rose-coloured glasses, she concedes. "The times were so much nicer then. Or were they? The music was definitely better. There were records that were like an event. Now it's like fast food."

But were times really better? Naysayers would argue that nostalgic-prone people hate change and are stuck in the past. The term itself comes from a Greek compound of nostros (return) and algos (pain), and was defined by Swiss physician Johannes Hofer in 1688 as a neurological disease.

Some artists have declared themselves anti-nostalgia. Take The KLF, who deleted their catalogue upon breaking up. This year they fulfilled their own prophecy of re-emerging 23 years later, but resolutely did not play any hits. One half of the duo, Bill Drummond, had previously issued a manifesto calling for people to "dispense with all previous forms of music and music-making and start again".

Then there's Joe Corre – son of Sex Pistols manager Malcolm McLaren and designer Vivienne Westwood, who last year – on a barge on the Thames – torched the collection of punk memorabilia he'd inherited, protesting that mass nostalgia for the era was "conformity in another uniform".

Not surprisingly, Karen Freedman agrees with the neuroscientists who think we shouldn't underestimate the power of nostalgia. Aside from her Countdown memories, she's now seen Paul McCartney play 111 times and enjoys the camaraderie it brings. "I don't need to pay for hotels across the world when he's playing because of the friends I've made following him around."

Perhaps my idea that nostalgia has no quality control is more a reflection on my own choices, because Gavin Wood would certainly contest that point. "The nostalgic songs are current today because they were incredibly written and performed," he insists. "I just bought Sergeant Pepper on new digitised CD and those songs are brilliant 50 years on. I rest my case."

Name: Alison Moyet

Famous hit: All Cried Out (2014)

Last original album: Other (2017)

Why you want to see her: Of all the electro talent that rose out of Basildon, Essex (Depeche Mode, Erasure, Yazoo), Moyet had the best soul voice

Playing: Margaret Court Arena, Melbourne, October 7. Enmore Theatre, Sydney, October 9.

Name: Yusuf / Cat Stevens

Famous hit: Peace Train (1971)

Last original album: The Laughing Apple (2017)

Why you want to see him: Ever since hearing that Eddie Vedder cover of Trouble you've rated Cat up there with Jack Johnson

Playing: Rod Laver Arena, Melbourne, November 27-28; Qudos Bank Arena, Sydney, November 4; ICC, Sydney, November 7

Name: Human League

Famous hit: Don't You Want Me (1981)

Last original album: Credo (2011)

Why you want to see them: You have unrealised dreams of being Susan and Joanne

Playing: Palais Theatre, Melbourne, December 13; State Theatre, Sydney, December 15

Name: Alanis Morissette

Famous hit: You Oughta Know (1995)

Last original album: Havoc and Bright Lights (2012)

Why you want to see her: To synchronise your cycle with 9000 furious women

Playing: Palais, Melbourne, January 22-23; ICC, Sydney, January 24

Name: Roger Waters (Pink Floyd)

Famous hit: Another Brick in the Wall (1979)

Last original album: Is This the Life We Really Want? (2017)

Why you want to see him: Let the young folk have their Sensation raves; Waters has the

the best lasers

Playing: Sydney Olympic Park Arena, Sydney, February 2; Rod Laver Arena, Melbourne, February 10-11

Classic Countdown airs on the ABC on Sundays, 6pm.