Extraordinarily, the study, which celebrated 50 years last year, has only had two directors, founder Dr Phil Silva until 2000, and Prof Poulton.
Prof Poulton was only 61 when he died last Friday evening. He was diagnosed with cancer three years ago.
Both directors exhibited strong empathy and compassion alongside their research skills and drive. Both encouraged trust and collaboration that would prove vital to the study’s achievements.
Both also recognised the profile of the study was important as it continued to secure money from various sources, notably programme funding from the Medical Research Council which became the Health Research Council.
It is extraordinary, too, that a study from a small city in the south of little New Zealand could become internationally famous and have international impacts.
As friend Prof Stephen Robertson said of Prof Poulton: "He took it to a level which actually defined elements of human development and human behaviour, which informed policy, changed law, changed the way we should think about human development and flourishing."
The study began with 1037 babies born at Queen Mary Maternity Hospital in 1972-73. It was supposed to see how they fared at age 3.
Now, the participants are in their sixth decade.
A quarter of the participants live overseas, and keeping track and returning them to Dunedin has not been easy.
The massive amounts of data cover the likes of dental and cardiovascular health, mental issues, drug use, criminality, relationships, sex, finances.
In 2018, for example, United States researchers used the data to link childhood lead exposure to adult mental health because the Dunedin Study offered the largest and longest psychiatric follow-up of adults who had had their lead levels tested as children.
The importance of self-control as a skill to be developed in children for healthier and happier lives was recognised. It was also found that future "dysfunction" can be identified in 3-year-olds, showing who was at most risk.
Another finding showed persistent cannabis use by teens resulted in an average eight-point drop in IQ. This was not recovered after the drug use stopped.
One 1993 paper showing the transient nature of much adolescent antisocial behaviour was used in many countries as justification for reforming their juvenile justice system to be less punitive and more supportive of young offenders.
Prof Poulton has said suggestions he would offer to new parents were to give their children unconditional love and set boundaries.
The nature versus nurture debate was shown to be a false dichotomy. Genes and environment work together in various ways.
Activation of a gene associated with depression and antisocial behaviour, for example, only happens if a child is mistreated.
The study began hand-to-mouth. An early temporary office was in the corner of a condemned Knox Church manse. Volunteer help was significant at the beginning.
From those small beginnings and under the leadership of two exceptional directors, the study has burgeoned. It has its own purpose-built centre on Anzac Ave.
The participants are due again next year to play their part again. They will help continue Prof Poulton’s legacy.
Biomarkers when they were tested aged 38 showed their biological age ranged from 28 to 61.
Why do some people age faster than others? The Dunedin Study is helping the world understand that question, and answers towards many others.
