I learned this past week just how ideologically homogenous my Facebook bubble usually is. Politically, I lean left of center. Almost all the people in my bubble are the same.

Said bubble has been built from the people I have met in the past 40 years or so. Most of these people are in marketing, digital media or tech. I seldom see anything in my feed I don’t agree with — at least to some extent.

But before all that, I grew up in a small town in a very right-wing part of Alberta, Canada. Last summer, I went to my 40-year high-school reunion. Many of my fellow graduates stayed close to our hometown for those 40 years. Some are farmers. Many work in the oil and gas industry. Most of them would fall somewhere to the right of where I sit in my beliefs and political leanings.

At the reunion, we did what people do at such things — we reconnected. Which in today’s world meant we friended each other on Facebook. What I didn’t realize at the time is that I had started a sort of sociological experiment. I had poked a conservative pin into my liberal social media bubble.

Soon, I started to see posts that were definitely coming from outside my typical bubble. But most of them fell into the “we can agree to disagree” camp of political debate. My new Facebook friends and I might not see eye-to-eye on certain things, but hell — you are good people, I’m good people, we can all live together in this big ideological tent.

On May 1, 2020, things began to change. That was when Canadian Prime Minister Justin Trudeau announced that 1,500 models of “assault-style” weapons would be classified as prohibited, effective immediately. This came after Gabriel Wortman killed 22 people in Nova Scotia, making it Canada’s deadliest shooting spree. Now, suddenly posts I didn’t politically agree with were hitting a very sensitive raw nerve. Still, I kept my mouth shut. I believed arguing on Facebook was pointless.

Through everything that’s happened in the four months since (it seems like four decades), I have resisted commenting when I see posts I don’t agree with. I know how pointless it is. I realize that I am never going to change anyone’s mind through a comment on a Facebook post.

I understand this is just an expression of free speech, and we are all constitutionally entitled to exercise it. I stuck with the Facebook rule I imposed for myself — keep scrolling and bite your tongue. Don’t engage.

I broke that rule last week. One particular post did it. This post implied that with a COVID-19 survival rate of almost 100%, why did we need a vaccine? I knew better, but I couldn’t help it.

I engaged. It was limited engagement to begin with. I posted a quick comment suggesting that with 800,000 (and counting) already gone, saving hundreds of thousands of lives might be a pretty good reason. Right or left, I couldn’t fathom anyone arguing with that.

I was wrong. Oh my God, was I wrong. My little comment unleashed a social media shit storm. Anti-vaxxing screeds, mind-control plots via China, government conspiracies to artificially over-count the death toll and calling out the sheer stupidity of people wearing face masks proliferated in the comment string for the next five days. I watched the comment string grow in stunned disbelief. I had never seen this side of Facebook before.

Or had I? Perhaps the left-leaning posts I am used are just as conspiratorial, but I don’t realize it because I happen to agree with them. I hope not, but perspective does strange things to our grasp of the things we believe to be true. Are we all — right or left — just exercising our right to free speech through a new platform? And — if we are — who am I to object?

Free speech is held up by Mark Zuckerberg and others as hallowed ground in the social-media universe. In a speech last fall at Georgetown University, Zuckerberg said: “The ability to speak freely has been central in the fight for democracy worldwide.”

It’s hard to argue that. The ability to publicly disagree with the government or any other holder of power over you is much better than any alternative. And the drafters of the U.S. Bill of Rights agreed. Freedom of speech was enshrined in the First Amendment. But the authors of that amendment — perhaps presciently — never defined exactly what constituted free speech. Maybe they knew it would be a moving target.

Over the history of the First Amendment, it has been left to the courts to decide what the exceptions would be.

In general, it has tightened the definitions around one area — what types of expression constitute a “clear and present danger” to others.  Currently, unless you’re specifically asking someone to break the law in the very near future, you’re protected under the First Amendment.

But is there a bigger picture here —one very specific to social media? Yes, legally in the U.S. (or Canada), you can post almost anything on Facebook.

Certainly, taking a stand against face masks and vaccines would qualify as free speech. But it’s not only the law that keeps society functioning. Most of the credit for that falls to social norms.

Social norms are the unwritten laws that govern much of our behavior. They are the “soft guard rails” of society that nudge us back on track when we veer off-course. They rely on us conforming to behaviors accepted by the majority.

If you agree with social norms, there is little nudging required. But if you happen to disagree with them, your willingness to follow them depends on how many others also disagree with them.

Famed sociologist Mark Granovetter showed in his Threshold Models of Collective Behavior that there can be tipping points in groups. If there are enough people who disagree with a social norm, it will create a cascade that can lead to a revolt against the norm.

Prior to social media, the thresholds for this type of behavior were quite high. Even if some of us were quick to act anti-socially, we were generally acting alone.

Most of us felt we needed a substantial number of like-minded people before we were willing to upend a social norm. And when our groups were determined geographically and comprised of ideologically diverse members, this was generally sufficient to keep things on track.

But your social-media feed dramatically lowers this threshold.

Suddenly, all you see are supporting posts of like-minded people. It seems that everyone agrees with you. Emboldened, you are more likely to go against social norms.

The problem here is that social norms are generally there because they are in the best interests of the majority of the people in society. If you go against them, by refusing a vaccine or to wear a face mask,  thereby allowing a disease to spread, you endanger others. Perhaps it doesn’t meet the legal definition of “imminent lawlessness,” but it does present a “clear and present danger.”

That’s a long explanation of why I broke my rule about arguing on Facebook.

Did I change anyone’s mind? No. But I did notice that the person who made the original post has changed their settings, so I don’t see the political ones anymore. I just see posts about grandkids and puppies.

Maybe it’s better that way.