It used to stop you in your tracks the moment you heard about a mass shooting.

Remember the reaction to the Columbine School shooting in 1999? The nation was captivated by the breaking news and glued to their televisions or radios getting all the details and analysis. We listened for weeks as the media and other experts analyzed the victims and the shooters. We wanted to find out why. We wanted to find out how to prevent this from ever happening again. We figured this was a tragic once-in-a-lifetime event.

My, oh my, how times have changed in 10 short years.

Now it seems like every week (or even more often) there’s a mass shooting reported in the news. It’s gotten to the point where it seems like the norm instead of the shockingly abnormal. Here’s a sample of what’s happened around us in the last month. Shootings left 10 dead in southeastern Alabama, eight killed in a North Carolina nursing home, six dead in Santa Clara, California, 13 more killed in New York earlier this month, three police officers gunned down in Pittsburgh and five children apparently murdered by their father in Washington State before he killed himself.

That’s six mass shootings that have taken 47 lives in just four weeks’ time. If that isn’t a sobering slap in the face to make you sit up and take notice, I don’t know what is. But we’ve become so immune to it all that it hardly fazes us, other than possibly a brief pause before we continue on with our busy lives.

Tragically, I think many Americans have become desensitized, almost numb to the mass murder, because it is no longer that unusual. We no longer even use the words “baffling” or “mysterious” when it comes to these massacres.

Our children have also become desensitized to real-world violence. Is it the violence on television? Is it the extremely violent video games? Through these mainstream venues we run the risk our of children learning that it is acceptable to use violence to resolve conflicts.

Children play lifelike video games in which people are killed without a thought. Movies and television programs show people being killed, also without a second thought, without consequences, or much less, a show of remorse by the perpetrator. If you grow up with that mentality, how do you develop any empathy for fellow mankind? How can you develop a sense of the value of human life?

Sadly, the world is a very dangerous place. We are no longer safe in our schools, churches, community centers, shopping malls. Who would have ever dreamt we are at risk of being gunned down in a nursing home? The regular occurrence of mass shootings has shattered that trust in a safe world for many people. It’s shattered the trust in humanity.

One man whose wife was one of the victims of the recent shooting in New York of the immigrants in a naturalization class asked, “What is it about American society that keeps turning out these kinds of people? What is it about our society that keeps driving people to do things like this?”

Good question. What is going on? What or who is to blame?

Is it a tendency toward copy-cat incidents, done by young, depressed males who are suicidal and desire the fame that comes with a horrific crime? But then again, there are plenty of people who fall on hard times, fail at school or relationships, or are bullied or victimized by others or society, and they don’t just snap and murder a bunch of people.

Is it easy access to handguns and rifles? I don’t think so. If someone has it in their mind that they are going to kill another person, they will find a gun, regardless of stricter gun laws and regulations.

What about lack of security at our schools and other crowded venues? We all know that issue has been addressed, and it is nearly impossible to safeguard every setting.

Sadly, we don’t know how to prevent mass shootings. We can’t pinpoint the moment when someone is going to snap and kill those around them.

We hear the stories in the news. We see the numbers of the victims keep rising. Each story is just another new statistic to add to an old story that doesn’t seem likely to go away. It’s a scary world in which we live.

I guess we take some comfort in the fact that our small corner of the world has not been shattered by such violence. But one pessimistically wonders if it isn’t just a matter of time.

Mullally is a Tribune writer.