The ageing space invaders machine in the lounge still gets a work-out. Participants in the Dunedin longitudinal study have gathered around it every time they have been called back for a new round of tests.
"We got it when they were 11 and we keep thinking we'll throw it away," says Prof Temi Moffitt, associate director of the groundbreaking health and development study.
"But when we call them and ask if they'll come in this year, they always ask, 'Will there be space invaders?'."
In between shooting at aliens, the 38-year-olds will test their fitness on an exercycle, open their mouths to a dentist, give blood, have their lung function measured and answer questions about their sex lives, finances and friendships.
Like the Video Village machine in the corner, they are also advancing in years. The oldest were born in 1972 - the year that Norman Kirk became prime minister, the Watergate scandal broke and Mark Spitz won seven Olympic gold medals - so the project they are part of is repositioning itself at the forefront of study into the ageing process.
Researchers have introduced new tests in a bid to find out why some people age faster than others, fully expecting that even though all the study members are 38, some will have the bodies of 25-year-olds while others will be more like 60.
The Dunedin Multidisciplinary Health and Development Study has tracked the lives of more than 1000 people since birth, in a project that has attracted international interest not only for its high participation rate but for its discoveries.
"There are much larger longitudinal studies," says the director, Prof Richie Poulton.
"But they have not measured people as frequently as we have or in the depth that we have or in the breadth that we have ..."
One of the study's great advantages is that it was founded as a multidisciplinary research project at a time when that was not in vogue, Prof Poulton says. Back in the early 1970s, people did not understand the interractions between various bodily systems, let alone between the body and the mind. Now those are exactly the type of projects that funding agencies want to invest in.
Not only does the Dunedin study have world-class data in areas such as mental, oral, respiratory and sexual health, but it can marry themes together and ask questions others cannot - looking, for example, at a possible link between gum disease and cardiovascular health or how poor mental health might "get under the skin" to cause physical problems.
The Dunedin study is also one of the lengthiest, says Prof Moffitt, an American who is in the city during assessments and spends the rest of her time at Duke University in North Carolina and King's College in London.
"People have caught on to the fact that improving health by treating people after they have a heart attack or diabetes or Alzheimer's is not working. So all the ageing research institutes in Britain, the US and Scandinavia are looking to find studies like this one that have got information from childhood. This is one of the few that started in the '70s and has continued going so long.
"Research information on health is one of New Zealand's greatest exports overseas and there's a huge market for it," she adds. "So when we publish a finding, researchers around the world try to jump on it and see if they can get the same thing."
One piece of research that shed light on why some people bounce back successfully from adverse life events while others become depressed has been tested by 147 other teams in 18 countries.
The world's most cited paper on mental health found the serotonin transporter gene comes in two versions - "short" and "long". The short version conferred vulnerability to stress whereas the long version provided protection.
When study members were 11, they were asked if they saw ghosts or heard voices that others did not. When followed up in their 30s, half of those who had reported such incidents had developed a serious mental illness. Now teams in 12 countries are surveying 11-year-olds in school and asking them the same questions.
In the study's early days, its findings led to safer playground surfaces and shorter cords on jugs, to prevent children pulling kettles down on to themselves and being burned.
More recently, it found that children suffering psychological maltreatment are more likely to have adult inflammation, a risk factor for physical problems such as heart disease, Alzheimer's and diabetes.
The study also revealed that people with a certain gene who are also mistreated as children are more likely to grow into violent adults - a finding that may explain why not all victims of child abuse grow up to victimise others.
And the same committee that awards the Pulitzer Prizes presented Prof Moffitt with the Stockholm Prize in Criminology for showing that antisocial acts are committed by two very different groups of people - those who remain offenders all their lives and a larger group who offend only during their teens.
Legal scholars used these findings to argue that the full force of the law should not come down on the latter group, who would otherwise end up with damaging criminal records.
The study has not only created a "reverse brain drain", attracting researchers from Britain, the US and Australia, but encouraged New Zealanders working overseas to settle back here, Prof Moffitt says.
Prof Murray Thomson, who discovered a link between cannabis smoking and gum disease, says the study was one of the main reasons he returned to New Zealand from working in Adelaide.
The "uniqueness" of the project was reflected in the fact that he as a New Zealand researcher gained $750,000 from the US National Institutes of Health for the previous assessment.
This time around, the Health Research Council has provided $1 million, believed to be one of the biggest grants made for oral health research in New Zealand.
Prof Thomson, from the University of Otago School of Dentistry, says when he first started going to international conferences and talking about the Dunedin findings, people were "gob-smacked".
"The study has an inherent interest to most people because it's about how people's lives turn out, how people negotiate challenges, trials and tribulations," Prof Poulton adds. "All the poets and novelists have written about this for centuries and here we have a scientific approach to those important, almost philosophical, questions."
Now the project that began as a child development study is for the first time being funded by the National Institute on Ageing in the United States.
One of the big questions facing most developed countries is how they tackle the increasing prevalence of age-related disease, Prof Poulton says.
While advances in medical care have seen longevity increase by two years every decade, the amount of time lived without disability has increased by only one year per decade - people are living longer but often with chronic health issues in old age.
"You can study people who are that age but in some ways the die is cast," he says. "So we see ourselves as having a particularly important role. Our people are just beginning to move into early middle-age, at which time we should see some evidence of them being on a good, an average or a not-so-good trajectory."
Once researchers identify risk factors, they can hopefully do something about them, and understanding why people do well is just as important.
Knowing everything about the cohort's early lives - whether they ate green vegetables at 15, when they started smoking, how much sport they have played - gives a clear picture of the type of things that characterise those who are "38, going on 25", Prof Moffitt says.
"And that's what we're looking for - how to slow down ageing."
With that in mind, returning study members will be asked to do cognitive tests for the first time since they were 13.
DNA was collected when they were 26 but new blood samples will allow researchers to look at RNA and genes that make people resistant to health problems or stressful experiences.
Researchers will also look at their telomeres - the end portions of chromosomes that have been likened to the tips on the ends of shoelaces that keep them from fraying. As cells age, the telomeres shorten.
For the first time, facial wrinkles will be photographed and assessed.
There are also two new, non-invasive tests to assess cardiovascular health. The first is to to measure the flexibility of the endothelium (or lining) of blood vessels by restricting the blood flow in one arm for five minutes, then releasing the pressure. Flexible vessels are healthy; stiff ones are not.
The other is to photograph the blood vessels in the eye, since their diameter is a reasonable indicator of the state of vessels elsewhere. The pictures will be graded by experts at the Singapore Eye Research Institute.
From now until April 2012, study members will visit the research unit - a former foundry office condemned for human habitation about the same time they were born - to tell complete strangers things they have never told anyone.
Interviewers will ask whether they have suffered illnesses, had emotional problems or engaged in illegal behaviour. They will also be questioned on everything from diet and drug use to how they and their partners divide up household tasks.
In this phase, they will be asked for more information than before about satisfaction with sexual relationships and difficulty getting pregnant, answering those questions by computer.
As in the past, interviewers will seek permission to check their police and medical records and to send a questionnaire to people who know them well.
Prof Poulton says the study's history of confidentiality and non-intervention encourages frank answers on delicate topics. The data is coded by numbers, not names, and never divulged to anyone else, neither partners, nor parents, nor police.
For volunteers who have piloted the tests over the past two weeks, the assessments have been an eye-opener.
Dr Nicola Brown says some of the cognitive tests were ones she had asked clients to perform earlier in her career as a clinical psychologist but she had never been "on the other side". The tests, measuring her memory, attention and analytical skills, were fun but extremely tiring.
"I'm a few months older than the study members so my classmates at school would every two years be going off for their [assessment] day and talking about it being fun... Now I'm aware of how incredibly significant the research is and I would have liked to have been part of it ..."
Study members do not get their test results. Evidence has shown that participating in the project has not improved their mental or physical health compared to other New Zealanders of the same age. And the $100 they are reimbursed for their eight hours at the unit is unlikely to be a drawcard.
Even being flown back to Dunedin and put up in a hotel for a few days is not such an attraction, now that many are in demanding overseas jobs, with only two weeks' annual leave and children of their own to care for.
The main reason 96% of them returned for the previous assessments was altruism, Prof Poulton says.
"The important thing to acknowledge is there's a tremendous reservoir of goodwill among the study members. They trust us with this incredibly important information about themselves ... and they entrust us then to do something good with it."
As well as creating what former Health Research Council chief executive Dr Bruce Scoggins described as perhaps "the richest archive the world will have on human development", the researchers have done something "good" with the data - translating science into a useful form for politicians and practitioners.
Ironically, no-one imagined the study that started in a church building and relied largely on volunteers would last more than a few years.
"They were going to be followed up at 3 and that was going to be it," says Michelle McCann, who joined the administrative staff in 1990.
"But it just keeps growing."
Now, as the age 38 assessment gets under way, staff are already making broad plans for further tests at ages 44 and 50. With each phase, the study becomes more valuable.
Measurements taken this year will form baselines for studies of ageing over the next 50 years, Prof Poulton says. Data collected now must be relevant for the research questions of tomorrow.
"We're constantly trying to figure out what's over the next horizon or the horizon after that and maximise the value of our research to ask and answer the important questions of the day."
FACT FILE
> The Dunedin Multidisciplinary Health and Development Study has tracked the lives of more than 1000 people born at Dunedin's Queen Mary Hospital in 1972 and 1973.
> At that time, technological advances were allowing doctors to save many babies who previously might have died but some were questioning whether difficulties such as preterm delivery and low birth weight were associated with problems later in life.
> The cohort were studied at birth, then followed up at the age of three. Further tests were conducted every two years until the age of 15, then at 18, 21, 26 and 32. In the next 20 months, as study members turn 38, they will return for their latest eight-hour assessments.
> The study has produced about 1100 reports, two-thirds of which have appeared in peer-reviewed journals. This is equivalent to one article every 13 days of the study. The first findings from the next phase will be written up in the second half of 2012.
> At age 32, 972 of the 1015 surviving members were seen - a 96% response rate, which is unheard of for a study of this type.
> About a quarter of study members now live overseas. A third are still in Dunedin.
> In 2% of cases, people who want to participate but cannot travel to Dunedin are visited by field workers. Some cannot travel because of work commitments. Others are in prison.
> In the past, study members have been more reluctant to give a blood sample and to test their fitness on an exercycle, than they have been to discuss sexual relationships or illegal behaviour. However, coverage at the most recent phase was still high - 93% gave blood and 90% did the cycling.
> Auxilliary studies have involved the cohort members' parents, partners and children.
> The next assessments, starting on Monday, will cost $2 million. Half the funds have been provided by the Health Research Council of New Zealand and the rest by overseas agencies. These include the British Medical Research Council and the National Institute on Ageing, in the US.
> Researchers wanting to collect data must obtain funds to cover their share of the study's costs. These expenses, which include flying study members back to Dunedin, accommodation and an on-site creche, work out to $7858 per minute of interview time.
> Two long-term research leaders from the United States, professors Temi Moffitt and Avshalom Caspi, have a sister study following 1100 pairs of twins born in Britain in 1994 and 1995.