Rules of thumb for forming an evidence-based opinion
Humans are opinion machines. Here are some rules of thumb to chasten your opinions and help pick decisions that are important to you and the collective well-being
How do we form opinions that matter in a world awash with information and misinformation? A mindful sceptic navigating complex environmental and social issues, is constantly challenged to separate fact from fiction.
This short guide offers six practical rules of thumb to help cultivate evidence-based opinions that can drive meaningful change.
Consider the bigger picture
Explore consequences
What if everybody did it
Question your motives
Challenge all opinions, including your own
Cultivate curiosity
And we form opinions all the time.
Take Sarah, for example.
Sarah and her coworkers were debating the merits of eating breakfast every day. Sarah insisted it was crucial for health and productivity, citing her personal experience. Her colleague, Tom, argued it wasn't necessary, referencing a famous diet guru's advice.
They didn't realise that their office debate reflected a much larger trend. A study by the Pew Research Center found that 81% of Americans trust their research on health issues as much as or more than professionals' recommendations. This statistic highlights how personal opinions and experiences often outweigh scientific evidence in day-to-day decision-making, even on important matters like health.
At a family gathering, Uncle Bob confidently declared climate change was exaggerated, based on a few cold days they'd had recently. His niece, Emma, an environmental science student, tried to explain global temperature trends but felt dismissed.
This scenario is surprisingly common. A Yale University study revealed that only 22% of Americans could correctly identify that almost all climate scientists agree that human-caused global warming is happening. This shows how personal opinions and limited experiences can overshadow overwhelming scientific consensus on critical global issues.
Sarah’s neighbours, Alex and Jamie, are new parents torn about vaccinating their baby. They found themselves swayed by emotional stories from anti-vax groups on social media despite their paediatrician's recommendations. And they are not alone. According to a study published in Health Psychology, 34% of parents ranked their personal experiences with vaccines as "very important" in decision-making. In comparison, only 16% ranked scientific research as "very important." This startling statistic demonstrates how personal anecdotes can sometimes carry more weight than scientific evidence, even in crucial health decisions.
It is personal for me, too.
Opinions
Recently, I came to the uncomfortable realisation that my opinions drive almost all of my decision-making. I know that over the years, a set of values and beliefs have glued onto my psyche, primarily uninvited, and yet are ingrained. I am fond of some opinions, some that I don't like, and a few that are scary.
I have a point of view on politics, the environment, the price of cheese, and everything.
Opinions are part of everyday human existence. They are what we do because, as my wife is fond of saying, we are ‘in and of this world’.
And in this world, we interact with other people. They all have opinions, too, and some are forthright with them. Some will even claim expert opinion.
So, I have to hold my ground and decide whether to agree with or acquiesce to more assertive personalities or be that strong personality myself and bruise my way to uphold my view of the universe.
And most of the time, I do this without evidence.
In other words, I have an opinion based on feelings, history, conditioning and indoctrination, much more so than on a logic-based examination of the facts.
Evidence-free opinions are the unavoidable truth. There's no point in saying I should be evidence-based or improve my use of evidence, even though that would be an advantage.
The reality is that we face too many decisions and situations each day. Applying evidence to every choice is too challenging, and our opinion system makes everyday life much more straightforward.
We can't live in the world if we're constantly unable to make even simple decisions.
The trick is to decide when to become evidence-based. What decisions are essential to individual and collective well-being? What decisions matter?
A mindful sceptic has a few rules of thumb that help.
Rule #1 Consider the bigger picture
The first is to become aware of the bigger picture. Not for every single decision, obviously, but now and again throughout the day, it's worth thinking, "Well, what's the bigger picture here?" Appraise the context and, perhaps, the available evidence.
A coffee analogy might help.
Ask where the barista got the milk when ordering a latte in the coffee shop.
How many cows are needed to provide latte on demand? No doubt the cows live far away from the cafe, so what sort of systems are required to safely put that milk in the barista’s hand with a healthy and regular supply?
Similarly, with the coffee. Where do the coffee beans come from? Presumably, it is not the same place as the milk. What processes did that coffee go through? It almost certainly travelled. Was it roasted on-site?
Indeed, what does a raw coffee bean look like?
So, think it through to become aware of the bigger picture.
Rule #2 Explore consequences
Another rule of thumb is to try and pick a consequence.
Imagine what would happen if I made an alternate decision. Such an alternative is called a counterfactual, an action or scenario that goes against (counter to) the facts.
In the case of the coffee, what would happen if I didn’t buy the latte?
I would feel cranky most of the morning. The coffee shop loses out on business that is unlikely to make or break them or affect the dairymen or the coffee growers in Costa Rica. In other words, next to zero economic consequences. To generate a cascade effect, it would take hundreds of regulars not drinking coffee because of a price hike or a COVID lockdown meant they worked from home.
The consequences of more significant decisions, such as ‘Should I buy this car? Should I buy this house? Should I leave this neighbourhood and move somewhere else?’ are life-changing and more likely to have broader consequences.
It is often worthwhile to consider counterfactuals and pick one or two to understand their implications beyond the self.
Rule #3 What if everybody did it
The third rule of thumb is to extend the consequence of a decision and imagine what would happen if everybody chose the decision.
The consequences would be dramatic if everybody had the inclination and wherewithal to join me for a latte to start their day.
Latte-swilling Westerners comprise roughly 10% of the world's population. If everybody in the world drank a morning latte, the supply of coffee from growers couldn’t cope with demand. Coffee prices would spike until more land area came under coffee production, assuming land with the appropriate soil and climate was available.
Coffee plantations and dairy farms would replace other crops, putting pressure on the grain supply for the muffin that occasionally accompanies the latte. In other words, there's a large-scale consequence of billions of people being able to access a morning latte—that’s before we even consider disposable cups.
Rule #4 — Question your motives
The fourth thumb-sized rule is to ask yourself why? Rather than walk into a coffee shop and order a latte, I ask myself why.
And for the latte, there's an apparent reason. I enjoy my coffee in the morning. It makes me feel good, thanks to the caffeine hit. I have the resources to buy a coffee and the opportunity, and I enjoy the smile on the barista’s face. A coffee means I start the workday with a little more well-being than otherwise. All of those reasons are legitimate.
But we notice that they're very personal, even self-centred reasons—my well-being and not necessarily the well-being of others.
I can imagine that the barista and the cafe owner are grateful for my custom, but my reasons for having a coffee are mine.
It turns out that most of our opinions and decisions are personal.
Beliefs are built over our lifetime as a combination of nature and nurture. We are told what we should believe, and much is absorbed in our existence.
Asking why a few times makes it easier to see that most opinions and decisions are self-centred and orientated around what is essential for us as individuals.
There's nothing particularly wrong or bad about being self-centred, given it is how human beings have become so successful. Personal makes perfect evolutionary sense. A focus on self promotes more making to fulfil our basic biology. We are constrained by this genetic profile and evolutionary history, which give us extraordinary capabilities but also bring consequences. And one of the big ones is that anyone will find it difficult to go against their innate biology.
‘Asking why’ will lead to personal reasons for decisions and choices. And if choices are made for family or loved ones, that's a personal feeling, too.
Again, it makes perfect evolutionary sense.
Challenge Your Assumptions: Are your opinions evidence-based or just comfortable habits? Use these rules of thumb to break free from mental shortcuts and make more informed decisions.
Extra guidelines for the mindful sceptic
Rule #5 Challenge all opinions, including your own
The mindful sceptic has another guideline to apply—to question not just everyone else's opinion but also to challenge your opinion.
When in a disagreement over something, almost always, another person's opinion clashes with yours. So the trick is to be sceptical about the other person's opinion, which is fair enough. Ask them where the evidence is and how they came to that particular belief.
But then do the same with your opinion and ask why you think differently.
Why do I have a latte, and you decide to have a long black or even choose to drink water and give me grief over exploiting the coffee growers of Costa Rica?
What is it that makes that difference? What evidence builds each opinion?
Perhaps there was no evidence involved. So, the sceptic in us should point out the lack of justification for those opinions. Maybe they just are and have come about as a result of your history and your personality.
This reflection can be quite confronting, and it will highlight the number of times that we do not use the facts to navigate life.
Rule #6 Cultivate curiosity
The last rule, ‘the thumb to rule them all,’ is... to be curious.
Curiosity leads us to ask questions and get to the bottom of things. It is also a great motivator to be deliberately evidence-based, consider evidence levels, undertake systematic reviews or meta-analysis, recognise the hierarchy of evidence, and learn about research methods and designs.
Now, we can't do this for every situation or every opinion. But going where your mind takes you and running with your curiosity is a core skill of a mindful sceptic and the route to adequate evidence.
One morning you might even order a chai latte. Or not!
How Sarah might apply the rules of thumb
Sarah begins her day scrolling through news headlines.
It’s terrible for her well-being, but we all do it. She pauses to consider the bigger picture before sharing an article about a new environmental policy. She asks herself: ‘What's the context here? Are there multiple perspectives I should consider?’ For once, she decides to read from various sources before forming an opinion.
Later, at the supermarket, Sarah contemplates buying organic produce because a quote from the article suggested it was a good idea. ‘What would happen if I always chose organic? How might this impact local farmers versus large corporations?’ She decides to research the topic more thoroughly before making a long-term commitment, dropping the certified strawberries into her basket.
During a team meeting about implementing a new recycling program, Sarah envisions widespread adoption. She thinks, "If every company in our industry adopted this program, what would the environmental impact be?" Even on the back of her mental envelope, the numbers look significant. The effect would be material, and she decided to advocate the initiative more effectively.
On her social media, she encounters a heated debate about electric cars. Before engaging, she questions her motives: "Am I responding to feel superior, or do I have valuable information to contribute?" She comments about where the electricity comes from for the EVs after reading an article on ‘Coal-fired Teslas’ on Mindful Sceptics.
At dinner, the conversation turns to a controversial local development project. Sarah challenges her opinions by asking, ‘Why do I support this project? Am I overlooking any potential negative impacts?’
Before bed, Sarah reflects on a complex issue she encountered during the day—the ethics of AI development. Rather than settling for a quick opinion, she cultivates curiosity. She makes a note to research more about AI ethics from reputable sources.
Sarah is nerdy but won’t repeat the rules of thumb to herself or tick each one off as her OCD would have her do.
All she needs is a second thought about them to help her make more informed decisions, engage in meaningful conversations, and develop a nuanced understanding of complex issues. She's not paralysed by indecision; rather, she's empowered by her ability to navigate the information landscape with mindful scepticism.
Rather than make Sarah's life more complicated, mindful scepticism simplifies it. By knowing when and how to apply critical thinking, she feels more confident in her choices and better equipped to contribute positively to her community and the broader world. And this is just a thought. It happens before Sarah spends any additional time gathering evidence.
Those rules again
Consider the bigger picture
Explore consequences
What if everybody did it
Question your motives
Challenge all opinions, including your own
Cultivate curiosity
Key points
Acknowledge that personal opinions often influence decision-making and are shaped by individual values and beliefs deeply ingrained in our psyche.
Opinions often stem from feelings, history, and personal conditioning rather than solely from logic-based examination of facts. Consequently, many opinions and decisions are self-centred, driven by personal experiences, and often revolve around what's crucial for individual well-being.
Relying solely on evidence for every decision is impractical in daily life due to the sheer volume of choices we encounter. However, a mindful sceptic counts on continual learning, challenging long-held beliefs, and being open to updating opinions based on new evidence and information.
A mindful sceptic will consider the bigger picture, assess consequences, envision wider implications, question motives, challenge opinions (including one's own), and foster curiosity.
Curiosity is a foundational motivator for pursuing evidence-based opinions, pushing individuals to ask questions, explore evidence, and strive for a deeper understanding of various perspectives.
In the next issue
The Science of Asking Better Questions.
What if the key to understanding our planet's most pressing environmental challenges isn't finding answers but learning to ask better questions? In our next issue, we'll dive deep into the art and science of curiosity. From visual thinking techniques used by top researchers to practical strategies for maintaining wonder in an age of information overload, you'll discover how to harness your natural curiosity for more effective environmental problem-solving.
Plus, we'll share real-world examples of how curiosity has led to breakthrough insights in ecology and conservation.
Know someone wrestling with eco-anxiety or drowning in environmental misinformation? Forward them this newsletter and help them find their path to confident, evidence-based action 🌍✨