Nitrates in drinking water have had a lot of press recently. File photo / Laura Smith
Nitrates in drinking water have had a lot of press recently. File photo / Laura Smith
Opinion:
When it comes to the supposed health impacts of nitrates in drinking water, ongoing repetition of statements gives the illusion of truth, Dr Jacqueline Rowarth writes.
For most of us, appropriate expertise is important. We choose mechanics for fixing cars, doctors and nurses for treating ailments, and dentists for repairing teeth, for instance.
We trust that the qualifications and experience of our chosen experts will lead to improvements in our cars and health.
Environmental activists and environmental NGOs seem to be outside the normal scrutiny.
These claims have not been substantiated by medical experts, yet the media gave Greenpeace airtime.
Early member (sometimes billed as a co-founder) of Greenpeace Paul Watson has said, “It doesn’t matter what is true, it only matters what people believe is true.”
Ongoing repetition of statements gives the illusion of truth. Researchers from the psychology department of Georgia State University have found that repeated information is often perceived as more truthful than new information, probably because repetition increases processing fluency.
This means that counteracting a public campaign is difficult.
Part of the problem is that scientists rarely say that they are 100 per cent certain of anything. Further, the process of questioning, tracking back for the source, thinking and rethinking (and sometimes reanalysing), and then setting new information in context, involves challenging the status quo, debate and rigorous discussion.
Because this sometimes happens in public, people use “it isn’t settled” or “there is still debate” without investigating the weight of the arguments.
Activists thrive on the uncertainty, and trust is now a global issue.
In 2022, the annual Edelman Trust Barometer, involving over 30,000 people in almost 30 countries, reported that distrust was society’s default emotion.
“Nearly 6 in 10 say their default tendency is to distrust something until they see evidence it is trustworthy. Another 64 per cent say it’s now to a point where people are incapable of having constructive and civil debates about issues they disagree on.”
Dr Jacqueline Rowarth. Photo / Supplied
The problem is that when distrust is the default, we lack the ability to debate or collaborate.
In New Zealand, the Acumen 2022 Trust Barometer reported only 41 per cent of people trusted media, 57 per cent trusted NGOs (and government) and 61 per cent trusted business.
Globally, most people know the importance of qualifications and of science. Pew Research, involving almost 15,000 Americans, reported last year that, although trust in many professions had declined since Covid, medical professionals and scientists still topped the list at 78 and 77 per cent, above the military (74 per cent), and police officers (69 per cent).
Only four in ten say they have a great deal or a fair amount of confidence in journalists and business leaders to act in the public’s best interests.
Like many professions, scientists have professional membership bodies, often discipline targeted and requiring specific qualifications for membership) which keeps an eye on standards.
Science isn’t like the medical or legal profession where unprofessional behaviour can lead to being struck off, but certainly, disciplinary action can be taken.
The same is true for journalism through the Media Council, requiring “accuracy, fairness and balance”. Given the current trust of 41 per cent of the population, the three principles need promotion. And adherence.
When it comes to environmental activists, however, discipline expertise does not seem to be a criterion for trust.
It seems strange that people with degrees in political science, social science or the school of life, should be more trusted than those with a degree in medicine, yet in New Zealand that appears to be the case when it comes to nitrate in drinking water.
The result is an unnecessary alarm and unnecessary expenditure on bottled water. And unnecessary work by regional councils (with a negative effect on the expenditure of rates).
The medical experts are the people with the most to lose in terms of their professional reputation if they get any interpretation wrong – which is why the “probability” of anything happening is always to the fore in discussion.
Further, scientists tend to think that once they have had a paper peer-reviewed and published and have explained the results of research in whatever public forum is appropriate, they can move on to the next piece of research.
In contrast, environmental activists echo their own statements.
Media have a role in preventing the illusory truth effect. The Georgia State University researchers explained that people tend to perceive claims as truer if they have been exposed to them before.
This “helps explain why advertisements and propaganda work, and also why people believe fake news to be true”.
The incidence of bowel cancer is high in New Zealand, hence the ramp-up in the national screening programme. Anybody concerned can check the dedicated website for preventative measures at bowelcancernz.org.nz and for the position statement on nitrates in drinking water here:
“Nitrates in drinking water are highly unlikely to increase the risk of bowel cancer in New Zealand, according to the current weight of evidence.”
Scientists and medical professionals are constantly scanning for and performing new research. They have found no link between colorectal cancer and nitrate in drinking water. These are messages which are both reassuring and worth repeating.
- Dr J.S. Rowarth, Adjunct Professor, Lincoln University, is on the board of directors of DairyNZ, Ravensdown, Deer IndustryNZ and NZ Animal Evaluation Ltd. The thoughts and analysis presented here are her own. jsrowarth@gmail.com
