In his book, Not Born Yesterday: The Science of Who We Trust and What We Believe, evolutionary and cognitive psychologist, Hugo Mercier argues that people are not as gullible as we’re led to believe. Most of us aren’t swayed by propaganda and carefully scrutinize messages for credibility and plausibility. Mercier relies on science and historical examples to show that individuals look for reasons to believe (new information) rather than reasons not to; and central to this tendency is a concept called plausibility checking, where receivers of messages and new information compare them to their own pre-existing beliefs and knowledge. When the two align, the message is more likely to be accepted; and when they clash, the receiver is more likely to be sceptical.

In his book, Mercier provides practical guidance on how to better judge incoming messages and information for truth; and through this, it’s possible to tease out useful, evidence-based insight into how to persuade others and pass the plausibility checks engrained in human psychology. With this knowledge, I present here a strategic framework for advocacy communications—which is centered around persuading agnostic or unsupportive audiences on a position—grounded in the insight offered by Mercier and the science underpinning it.

Consideration 1: Identify your audience and their values—not yours. What do they care about?

This is probably the most important consideration for any communications advocacy campaign and the most common mistake designers of those campaigns make. Knowing who you’re speaking to and framing arguments to align with their values—not yours—is critical. For example, in the case of the contentious issue of drug decriminalization where there are many opposing views, arguing for this policy by underscoring how it will reduce stigma will not resonate with someone who doesn’t care about the stigmatizing effects of criminalization. These individuals are often more concerned about public safety and street disorder; therefore, fashioning an argument that articulates how decriminalization will reduce street disorder and make neighbourhoods safer (if in fact, it does these things) is a more effective framing that will have a better chance at changing that person’s mind by passing their plausibility checks. The misalignment between sender and audience values is often seen in activist social movements where arguments are often framed as a matter of justice and equality and presented to an audience who cares more about economic stability and public safety.

Consideration 2: Communicate through your audience’s trusted sources

One of the most effective ways to persuade others is to have the messenger match the audience. Doctors should speak to doctors, policemen to policemen, liberal to liberal, conservative to conservative. Having someone your audience trusts and can relate to representing your ideas will have a greater likelihood of winning support for a position. We are hardwired to trust our peers or those who share our values, beliefs, and social characteristics. We’re more likely to listen to and take seriously what they have to say.

Consideration 3: Make your messages “intuitively appealing” (appeals to common sense)

When possible, framing an argument or position in its simplest most logical form while appealing to common sense is an effective way to win support for it. This is especially true now because of the pervasiveness of digital distractions at our fingertips eroding our attention spans and willingness to unpack complexity. “Because drugs are highly addictive they are fuelling an overdose crisis; therefore, they are dangerous and should not be legal,” is an example of an intuitively appealing argument. It is clear, simple, with logic that’s easy to follow, and appeals to conventional views on drugs presented in mainstream media. These factors help the argument pass most plausibility checks. “Treatment and recovery services for addiction are inherently good and should be supported,” is another example along the same lines. Trying to argue otherwise will not win you much support, e.g., see comments to this post. Don’t make your audience work: Avoid couching positions in complex, academic arguments that force people to reflect too deeply, because most won’t—not because of inability, but because of desire.

Regardless of one’s political leanings, this video by Pierre Poilievre is a strong example of leveraging intuitively appealing arguments. The information is clear, the logic is easy to follow; and because of these factors, it just feels (intuition) correct and is therefore persuasive.

Other Considerations

You can also strengthen your arguments by considering the following (also mentioned in Not Born Yesterday):

• How close is the messenger to the information? An eyewitness is more credible that someone who heard it second hand.
• What is their track record of being right? This is a hard signal to fake; so if the track record is good, reference it.
• Is this a majority view? Majority views are seen as more credible.
• Appeal to science—especially math and statistics from a credible source—as this makes the sender seem more knowledgeable.