Witnesses' failure to stop a public assault on British celebrity chef Nigella Lawson is not surprising, New Zealanders might not have intervened either, specialists say.
Art collector Charles Saatchi, 70, publicly abused his wife Lawson, 53, at a London restaurant on June 9.
Fellow diners reported a heated argument, during which Saatchi repeatedly grasped Lawson's neck, pushed his hands into her face, and pinched her nose.
Lawson appeared upset and left the restaurant in tears, passers-by said. But while witnesses photographed the incident, no one reported the crime to the police.
Saatchi initially dismissed his actions as "playful" but had now accepted a caution for assault.
Helping out during public emergencies was "more complicated'' than it seemed, lecturer at Auckland University school of psychology Danny Osborne told Fairfax Media.
Studies showed there were five stages to negotiate before people were moved to step in, Osborne said.
The first stage was noticing. Then came interpreting the problem, accepting responsibility for providing help, deciding what to do, and then doing it.
"This was an instance in which people either failed to take responsibility or perhaps they felt responsible but decided not to help," he said.
The larger the audience to a domestic assault, the less likely someone would feel responsible, Osborne said.
In deciding whether to help, people internally evaluated "the pros and cons of interfering".
"Cons might include embarrassing yourself if you find out that the woman didn't require assistance," he said.
National Network of Stopping Violence general manager Parekotuku Moore said New Zealanders were becoming less tolerant of domestic abuse, and she encouraged witnesses to intervene and seek help.
"Foremost, [intervening] sends a message to the victim that what is happening is observed and is not acceptable.
"It is important to let those involved know the incident has been watched, and that there is intention to take some action. It might be to get involved, or to call for further assistance," she said.
Statistics showed New Zealand had a high rate of domestic violence, with between 33 and 39 per cent of women experiencing physical or sexual violence from a partner in their lifetime.
The New Zealand Medical Association associated domestic violence with "increased risk of depression, anxiety, substance abuse, and self-injurious behaviour, including suicide".
Of those arrested for family violence, 84 per cent were men. Police estimated just 20 per cent of domestic violence was reported.