People are less likely to post political comments on Facebook if they believe they are in a minority on controversial issues such as legalising cannabis, a survey has found.

The UMR survey of 1000 New Zealanders, included in a new report on Digital Threats to Democracy, used the cannabis issue to test theories that social media cause "spirals of silence" and polarisation of views.

The poll, taken last September and October well before details of a referendum on the issue were announced yesterday, found that 58 per cent supported decriminalising cannabis and 35 per cent opposed it.

It also found that 61 per cent of those who thought a majority of New Zealanders agreed with them, but only 39 per cent of those who thought they were in a minority, would be willing to post their views about it on Facebook.


"People who thought their views were different from the rest of New Zealand were significantly more hesitant to discuss the issue on Facebook," the report says.

"Those who thought their views were shared were less hesitant to discuss them on Facebook - in other words, a belief that views were shared by the majority of people lowered barriers to discuss the issue online."

People were not always accurate in what they thought the majority view was.

Two-thirds (63 per cent) of those who supported decriminalisation correctly believed that that was the majority view.

But only 35 per cent of those who opposed decriminalisation believed they were in the minority. Another third incorrectly thought they were in the majority and a third were unsure.


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The survey found that people were also less likely to express their views on cannabis in a face-to-face situation at work if they thought their views were not shared by their friends and family.


"However, those who believed friends and family held different views were still willing to discuss the issue on Facebook. This finding suggests that social media may, for some people, be a tool to share their views when they believe family and friends don't agree with them," the report says.

"We did not ask where on Facebook these views were shared, it may be that Facebook groups offer a space to discuss views not shared within a person's direct social group."

When the question was widened to ask about whether people believed a majority of all New Zealanders agreed with them, those who believed they were in the minority were less likely to express their views at a community meeting or at a restaurant with friends - but were still willing to speak up at work or at a family dinner.

"In other words, a belief that others held different views did not reduce willingness to discuss that issue in some in-person settings," the report said.

But it concluded: "Our finding replicates international findings. Social media in New Zealand, notably Facebook, may not be a forum in which people who believe they hold minority views feel they can discuss those views more easily."

The poll found that 87 per cent of New Zealanders used Facebook, 24 per cent used Twitter and 21 per cent used Instagram.

However when asked where they got information about decriminalising cannabis from, 78 per cent said they got it from TV and radio, 63 per cent from friends and family, 61 per cent from online news sources such as the NZ Herald and Stuff, and 53 per cent from printed media.

Of those who used social media, 58 per cent got their information from Facebook and 50 per cent from Twitter.