It's just that threat that Williams, a senior lecturer in psychology at Massey University, aims to get to grips with in his new project, supported by the Marsden Fund.
"Social media can provide a megaphone for those sharing misinformation, and I worry about the harm that misinformation can cause," he said.
"That said, I don't believe there is currently strong evidence that people are any more likely to believe misinformation or conspiracy theories now than in the past.
"Sharing misinformation and conspiracy theories is something humans have done for a very long time."
Williams described a conspiracy theory as an attempt to explain some significant event as the result of powerful people or organisations secretly plotting to achieve a malevolent goal of some sort.
And that wasn't to say that conspiracies didn't actually happen - the Watergate scandal being perhaps the best-known example - and many could be supported by evidence.
"But something that makes conspiracy theories interesting to us in psychology is that people often seem to believe strongly in conspiracy theories that are very inconsistent with the available evidence," Williams said.
"An example would be the theory that the symptoms of Covid-19 are caused by the 5G mobile network.
"And sometimes such conspiracy theories can cause harm - as we saw when some people set fire to cell phone towers right here in New Zealand."
Over recent years, particularly, psychologists have become more interested in these theories, and much of their research looked at how people who believe in them differ from people who don't.
Some past research has suggested that people who experience more stress and who trust others less are more vulnerable.
Yet, while experts are building up more knowledge, one major question remains unanswered: what leads someone to change what they believe?
"That's the big-picture question we're seeking to answer in this study," Williams said.
"Secondary to this big overarching question, we want to answer some more specific questions: When people do change their beliefs, what do they describe as the reasons for these changes?"
"And do negative psychological experiences such as stress, depression, and reduced trust lead to increased belief in conspiracy theories?"
For more on the safety of the Covid-19 vaccine and other things you need to know, listen to our podcast Science Digest with Michelle Dickinson
In their study, Williams and his colleagues will collect data from the same group of people repeatedly over time, to look at how much they change, and why.
"We hope to recruit a sample of 1000 people for 25 data collection points over two years," he said.
"This longitudinal design will allow us to study change over time, and it'll also allow us to draw more credible conclusions about causal effects than a one-off survey.
"As far as we know, no previous study has tracked people's belief in conspiracy theories for as many data collection points as we plan to."
That could enable them to quickly identify cases where someone had switched their beliefs, and then ask them about why they changed their mind.
"We're also planning some complex statistical techniques that go beyond what's previously been used in this area of research," he said.
"This includes temporal network analysis, which will allow us to look at whether developing a belief in one conspiracy theory leads to belief in others."
While the project's purpose wasn't to test strategies to fight misinformation, he hoped that getting a deeper insight could inform interventions in the future.
Williams added that questions surrounding Covid-19 would feature in the study.
"For example, we will probably include the theory that the Covid-19 vaccine contains microchips intended to monitor and control people," he said.
"We think it's important to us to focus on contemporary conspiracy theories like this one, where it's likely that people might change their mind in the next while.
"In contrast, I'm not sure many people will change their mind over the next couple of years about whether the moon landings really happened."
