Aggie Auelua. Photo / Supplied
On a quiet beach in northern New South Wales, Norma Hennessy attended a moving ceremony two weeks ago to pay tribute to the brave Kiwi woman who died while saving her young grandson.
Agnes "Aggie" Auelua, 25, died on October 10 after jumping into the sea to rescue her friend's 9-year-old boy swept off rocks near Fingal Head lighthouse.
Her family said Aggie could hardly swim. They remember her as a helpful, friendly and happy person who made a positive impact on her community in Wellington's Hutt Valley.
To Hennessy, she will forever be a selfless hero who paid the ultimate price to rescue her grandson, Matt.
"Matt was the stronger swimmer and when a man got out to them with a board, Matt asked him to take Aggie back first, but she insisted he took the boy," she says.
"By the time more help got to her she was gone. Aggie was extraordinarily brave and it was a tragedy she didn't make it."
Just four days after Auelua perished another Kiwi died while saving a group of young children in Samoa from being mown down by an alleged drunk driver.
Auckland father-of-two Christopher Limu, 29, was killed when hit by a car near his family's village Falefa, east of Apia.
Childhood friend Elisha Lane told One News he "always had a big heart" and in her eyes had "died a hero".
In the face of enormous peril what would you do? It's a favourite pub conversation, but thankfully not something many of us have to face.
Scientists have long puzzled over what drives some people to become selfless rescuers while others freeze.
We are raised to think twice before we act, especially when faced with a potentially life-threatening situation.
Friends and loved ones tell us "not to be a hero" and police usually advise us not to confront dangerous people. Yet some are compelled to act.
A study in the United States into why some individuals take extreme risks to save others reveals these types of rescuers tend to disregard all that advice.
If you stop to think whether to act when the danger confronts you, you probably won't, the report - by Yale University scholar David Rand and Zev G. Epstein of Pomona College, California - suggests.
In an interview with the Washington Post, Rand describes this "danger of deliberation".
He says it is the biggest deterrent to what he calls "extreme altruism".
"The people who act are the people who have a sort of co-operative impulse and are people who don't overthink things," Rand says.
"It is the kind of thing that if you stop and think about it you start coming up with reasons you shouldn't act."
The study is gleaned from interviews with recipients of last year's Carnegie Hero medal.
The awards are given annually to individuals in America who risk their lives saving or trying to save others.
Asked about their feats of courage, one unidentified respondent reveals: "The minute we realised there was a car on the tracks, and we heard the train whistle, there was no time to think, to process it. I just reacted.
"I think when we are forced into this kind of situation you become a different person."
Rand found it "weird" to spend so much time researching the issue and come to the conclusion that extreme heroes are individuals who go with their gut.
"These results," says the study, "suggest that the decision-making process described by the Carnegie Hero medal winners were predominantly driven by intuitive, fast processing."
Brave teen Kiwi rescuer James Lee ticks many of the boxes mentioned in Rand's report.
Lee was just 16 when he saved four people from drowning within an hour at Hot Water Beach on the Coromandel two years ago.
He first rescued two boys, aged 9 and 11, who were being dragged out by powerful currents.
Within 10 minutes of pulling the lads to safety, he had to rescue a middle-aged Turkish man who couldn't swim.
While he was hauling the man to safety, another male in his 20s needed help, too.
Lee, a member of the local surf lifesaving club since he was 10, was at the beach visiting his parents during the school holidays. There were no lifeguards on duty at the time and he had no lifesaving equipment.
"Looking back, I'm surprised at how I never thought twice about it," he says. "A lot of it kind of went against my lifesaver training.
"When the drama all started I was overcome with with this very powerful clarity, like I was on an unstoppable mission to save these people.
"It was quite remarkable how I managed to make all the right decisions because I was getting emotionally and physically drained as one situation quickly followed another."
Lee says the only time he considered himself to be in danger was when he reached the Turkish man who was clearly drowning.
"For a moment I realised I had no gear, no back-up and the guy couldn't swim," Lee says.
"The waves were coming over his head and he was in serious trouble.
"I briefly worried he could put me in trouble too because he was heavy and when I got to him I couldn't move either. But the adrenaline kicked in again when I realised someone else needed help too and I somehow got him to safety.
"At no stage did I think that I shouldn't be doing this."
Lee says it was only afterwards he realised the danger he had been in.
"I was really giddy and laughing hysterically. My heart was pounding but I wasn't cold.
"If it happened again, I think I would still do it."
Social and neuroscientists have been wrestling since at least the 1960s with the question of why some act and others don't.
But some believe the answer is not so simple as Rand has put forward.
Danny Osborne, lecturer in psychology at the University of Auckland, says deciding to be a rescuer can involve a complex five-stage mental process.
"The first stage is when people notice something is wrong, then they have to interpret what they are seeing," he explains.
"They then consider the level of responsibility involved and if there is anyone else around who could also help.
"This is followed by the decision to act and a consideration of how guilty they might feel if they didn't do anything.
"Helping is a lot more complex than most people assume and all of these stages can occur in a matter of seconds. If any of these five things go wrong it can result in a failure to intervene."
Research has not yet uncovered a definitive personality trait - or a gene - that might determine why some people become heroes and others don't, Osborne says.
"There is evidence to suggest that people who are in a slightly negative or depressed mood might be more inclined to help to make them feel better about themselves.
"But the process of deciding to help or not can simply come down to how someone feels emotionally at any particular time.
"This can change from moment to moment and can be very situation-specific."
The decision to put your own safety at risk is further complicated when a number of other people are present who could potentially step in to help - or not.
Two recent incidents that made international headlines highlight this dilemma.
In July, there was uproar in the United States when almost a dozen witnesses stood by and did nothing while 24-year-old Kevin Joseph Sutherland was brutally stabbed to death by a teenager on a Washington subway train in the middle of a holiday afternoon.
A few weeks later, five men including two American soldiers, were given the Legion of Honour in France for subduing an armed terror suspect on a French train. One of the Americans and another passenger were seriously hurt.
Authorities said a massacre might have occurred if not for the heroics of the men who attacked the suspect aboard the high-speed train travelling from Amsterdam to Paris.
The alleged gunman, identified as Moroccan national Ayoub El Khazzani, carried an AK-47 assault weapon, nine magazines of ammunition, a Luger pistol with extra ammo and a box cutter.
Dr Jackie Hunter, lecturer in social psychology at University of Otago, believes the decision of witnesses to do nothing during the Washington subway incident could be down to a simple "bystander effect".
"It could possibly have been a result of diffusion of responsibility - that someone else would help," Hunter explains.
However, in the case of the French train drama several people, including the soldiers, deciding to intervene at the same time was an important element.
"If the situation is clear, people who have support are more likely to intervene and so be heroes," Hunter says.
"Also, if people have specific skills and perceive themselves to be competent, strong, have prior training or knowledge of first aid, then they are more likely to intervene if someone is under attack.
"Such people can be said to be 'principled' risk takers."
We will never know what went through Aggie Auelua's mind in the moments before she jumped into the surf to save 9-year-old Matt in New South Wales.
All we know is that she gave her life to save another and Norma Hennessy says she and her family will be forever grateful for that heroism.
"I feel so sad for Aggie's family but what she did for my grandson that day was very selfless and very courageous. Not many people could have done what she did."
The woman was shaken by the incident.