The heckler was an eighth-grader. I was teaching youngsters about journalism at a middle school in suburban St. Louis this spring, and when I got to the slide labeled “Fake News,” a boy yelled “CNN!”

Most of the class laughed.

“What do you mean by that?” I asked. I wanted him to think about what these words really meant. His heckling gave me a chance to ask a few more questions: Did he believe a news network was making up stories out of thin air and broadcasting them? Did he believe they were presenting facts from a biased perspective? Or did he just not like the stories they reported?

This student struggled to say exactly what “fake news” meant. Nowadays, it’s used as a joke or throwaway phrase when you disagree with someone. A similar exchange about “fake news” played out in every class I taught that day. It opened my eyes to the extent of one of the biggest problems facing parents and educators: How do we raise children in a post-truth world?

Originally, “fake news” referred to deliberately false stories designed to influence public opinion. One analysis found that fake or hoax stories got more reader engagement on Facebook than real news stories during the last three months of the 2016 election. Russian propaganda mills banked on Americans’ inability to separate fact from fiction.

But something far more sinister than naivete has crept into the understanding of “fake news.” President Trump revealed it in his own words, tweeting: “The Fake News is working overtime. Just reported that, despite the tremendous success we are having with the economy and all things else, 91 percent of the Network News about me is negative (Fake). Why do we work so hard in working with the media when it is corrupt? Take away credentials?”

The president defines “fake” as “negative” stories about him. For him, a provable, real fact turns “fake” because it makes him look bad or he doesn’t like it.

That’s not how facts work. Information that can be demonstrably proven true does not become untrue because you disagree with it. Let’s say it one more time for those in the back: Just because you don’t like it doesn’t mean it’s fake.

For example, here’s a fact that I do not like, but is true nonetheless: I occasionally make errors in my stories. I hate when it happens, but it does, and I’ve had to correct those errors. Here’s another: St. Louis has high levels of gun violence. It’s an unfortunate fact, but one I can’t deny exists. One more: Obamacare increased the number of insured Americans, but also caused problems that need to be fixed. It’s possible to agree with the values of a policy objective and still accept the facts that reveal its shortcomings.

Historically, this is how we have understood facts and truth to work. They stand independently of our feelings.

Initially, when we were concerned about whether young people would be able to tell if information was true or not, we taught them to visit other independent sites to try to verify what they had seen. We can teach them to check Internet rumors on independent fact-checking sites like Snopes.com, Politifact.com or FactCheck.org.

But now we have to back up in this conversation. Let’s start with why truth matters. And let’s ask ourselves: How do you feel when your children lie to you? How would you react if your spouse lied to you? What about your boss or your doctor?

We would all be legitimately upset if our children, spouses, bosses or doctors lied to us. How can we make decisions about our lives if we can’t trust people to tell us the truth? Our basic autonomy depends on being able to tell what is real and what is not.

Cognitively, people are wired to believe what they want to believe. A significant percentage are willing to discount facts if they challenge what they “feel” to be true. Feelings can be swayed easily, as our emotions can be separated from logic and reasoning. The spread of social media and agenda-driven opinion shows allow people to stay in a bubble of what feels true as opposed to what is true.

So we have to be super clear about what words literally mean.

“Fake” means false or untrue. “Negative” means unfavorable or disagreeable. These words mean entirely different things. Something can be negative and also 100 percent true.

When our children can no longer tell the difference between fake and negative, when they don’t understand what “fake news” is and how it can be used as a political tool, when they are willing to disbelieve their own eyes and ears, that’s when they’ve lost their freedom.

In my discussion with the skeptical eighth-grader, I pointed out that if he only wanted news to exist that supported his preferred political party or candidate, we would end up with media a lot like North Korea’s.

No one found that scenario very funny.

One in two American children will develop a mood or behavioral disorder or substance abuse addiction before age 18.

When I read this statistic in Katherine Reynolds Lewis’ new book, “The Good News about Bad Behavior,” my reaction was: Wait, what?

I have been hearing anecdotally for years about an epidemic of anxiety, depression and substance abuse among kids, but could it really be this widespread? Lewis had the same reaction when she found the government data by the National Institute of Mental Health that looked at more than 10,000 children.

“I was so shocked,” she said. “Why was this not on the front page of every newspaper?”

A veteran journalist, she dug into the study, reported it out and found the only people who aren’t surprised by the research are high school guidance counselors and mental health professionals -- the ones on the front lines of this crisis. In fact, 32 percent of children have an anxiety diagnosis, she said.

Lewis builds a convincing case with a substantial amount of research that we are seeing an actual change in children, not just a rise in diagnosis. This is coupled with a documented rise in misbehaving, undisciplined children, she writes.

“Children today are fundamentally different from past generations,” she writes. “They truly have less self-control.” Her book explores why and what to do about it.

As a parent, it’s a relief to hear this confirmed. Many of us had the suspicion that our children and their peers were growing up fundamentally different than we did. Lewis explains why this might be: We had a lot more independence, more responsibility around the house, more unstructured time and free play. We could take more risks, had to learn to manage our own time and work out our own conflicts at a younger age. All of this helped us practice and learn self-regulation.

The other massive sea change is the explosion of media in all aspects of kids’ lives, bombarding them from ever-younger ages and for longer hours. The messages they often get from being immersed in social media: You are not good enough, and everyone else is having a better life. No wonder we are seeing skyrocketing anxiety in younger generations.

“We have to recognize that our kids need so much more support to manage their behavior and emotions than we did when we were growing up,” she says. The parenting techniques our parents used will not work on our children because they are growing up in such a different way. That’s not to say our parents were wrong, Lewis said. We just need new parenting tools to cope with how modern childhood has changed.

She makes a radical argument: Traditional punishments and rewards simply do not work to raise capable children. These techniques are not helpful long-term and only create extrinsic motivation rather than building intrinsic motivation. Instead, we need better connections with our children, smarter consequences and more consistent boundaries with them.

So, how do we do this? It can be confounding, especially for those of us raised with a very different parenting style of strict rules and the fear of breaking them. Lewis says to begin with managing our own response before we respond to a child’s misbehavior. Even 10 seconds of breathing will calm our physiology, and children mimic our heart rate and breathing. We can either help them calm down or ramp them up even more, she said.

Then, find some small way to connect before you talk about the problem. Use a language of respect and mutual agreement. Set and enforce limits, and be willing to live with the natural consequences if those limits are ignored, she said.

Lewis has been a parent educator for years and is raising an 11- and 14-year-old, along with having helped raise a 25-year-old stepdaughter. Her tween and teen are allowed 30 minutes of screen time per day during the week, after they finish their homework, household chores and music or sports practice. No screens are allowed in the bedrooms. Cellphones and devices are turned in no later than 8:30 p.m. If they need their phone while doing their homework, an adult is nearby to help keep them on task.

“I’m looking forward to when they can self-regulate that,” she laughed.

I was amazed to hear how she and her husband have managed to set and enforce such limits without constant nagging, yelling and battles.

Ultimately, the challenging message she shares with parents is a hopeful one.

When my sister was trapped in her car, which was laying perpendicular on the freeway after flipping over several times, she could overhear people talking nearby.

“Is she alive in there?” someone asked.

She wanted to yell: Yes! I’m alive, and I can hear you!

Firefighters eventually cut her out of her crushed Lexus. First responders put her on a stretcher and took her to the nearest trauma center an hour away in Bryan, Texas. She was in pain, but conscious and answering the questions the EMS workers asked.

My sister, Rabeea, is an attorney and had been driving back from a deposition in Austin. She asked if she could call our mom to pick up her boys from preschool. They live in a suburb of Houston about two hours from the accident site, and her husband was out of town on a work trip.

In a reminder of how small the world can be, the EMS worker turned out to have attended high school with my sister nearly 20 years ago, though they hadn’t known one another in their huge suburban school. He was doing his best to calm her and take care of her when no one knew the extent of her injuries. He told her that her seat belt, which had cut into her shoulder and hip, had saved her life.

It’s terrifying to get a call that someone you love is being taken to the hospital. I think it’s worse when you are far away and can do nothing but imagine the worst and wait. Incredibly, Rabeea survived with just a few broken ribs, cuts and bruises.

When I heard she was OK, that’s when I cried. Tears of relief, mostly. Grateful that God had spared her life, that laws have made buckling up a habit for us, that firefighters, EMS workers and doctors had taken care of her, that her brain and body were intact, that my sweet nephews still had their mother.

My brother drove Rabeea back home once she was released from the hospital, and my mother went to stay the night with her. Doctors had given my sister a shot of morphine and a prescription for painkillers. My mom went to pick up her medicine from the pharmacy. It was dark and the street was poorly lit. She turned wide, and her car fell into a ditch.

I hadn’t been able to sleep anyway, so I was awake when my sisters started texting about my mom’s accident. Some nights you know you aren’t going to sleep at all.

A small group of bystanders gathered around my mom while she waited for a family member to come pick her up and a tow truck to move her car. She had her hair covered, like she always does in public. Five different people stopped to help her and stayed with her until my brother-in-law arrived. Thankfully, she hadn’t been injured.

She called me later to say how touched she was by the kindness of the strangers who waited with her.

“I was wearing my hijab, and it was midnight,” she said. “They were all so nice to me.”

It reaffirmed her belief in the goodness of people. Moments like that always do for me, too, but I felt a little sad about how grateful she sounded. Why wouldn’t people be nice to a grandma stuck in a ditch in the middle of the night regardless of whether she wore a headscarf? I didn’t say that aloud because even in my head I realized how naive it sounded.

Both accidents happened on my father’s birthday. I hadn’t called him while we were waiting for updates on my sister because his anxiety in such situations just exacerbates my own. When I did talk to him, we agreed to focus on what had been saved and let go of what had been lost.

The next day, in our sibling group chat, we texted about how crazy that day had been. One sister shared a quote from George Saunders’ commencement address in 2013 at Syracuse University as a reminder of how we should strive to treat one another: “What I regret most in my life are failures of kindness. Those moments when another human being was there, in front of me, suffering, and I responded ... sensibly. Reservedly. Mildly.”

Every day, I read news stories about people’s incivility or outright cruelty to other people. Sometimes these stories break my heart, and sometimes I’m not even surprised because it’s so common.

The first responders who helped my sisters and the bystanders who stood by my mother were unreserved in their kindness. They took care of people I love when they were alone and scared and hurt. I hope I am never too distracted, too self-involved or too sensible in the face of someone’s suffering.

Because it’s kindness that saves us.