During the ‘70s and ‘80s, psychologists warned society about the dangers of television. Watch too much, they said, and our brains would turn to mush.

Canadian scholar Marshall McLuhan called television “a vast wasteland.”

You have to wonder what Mr. McLuhan would say about today’s violent video games. Instead of mush, research seems to show that violent video games are turning our children’s brains into a mass of hyper-aggressive gray matter.

In 2004, noted researcher Dr. Douglas Gentile warned parents of the possible effects of video games in an article published in Pediatrics for Parents. Mr. Gentile admits that video games can have positive effects because they “are natural teachers. Children find them highly motivating by virtue of their interactive nature. Children are actively engaged with them. They provide repeated practice, and they include rewards for skillful play.”

That’s great. But exactly what are they teaching?

Early games such as “Pac Man” and “Super Mario Brothers” were considered violent because the main character could die a number of ways. In addition, the main character had to slay a variety of creatures to progress through the game and eventually win.

Those games seem quaint by today’s standards.

Advances in technology mean today’s games are more sophisticated, and, though they take place in a fictional world, the blood and gore is pretty realistic. Yahoo recently listed the 10 most violent games on the market today. Let’s look at one of those on the list, “Grand Theft Auto: San Andreas.” Here’s Yahoo’s description:

“Player is a young man working with gangs to gain respect. His mission includes murder, theft and destruction on every imaginable level. Player recovers his health by visiting prostitutes then recovers funds by beating them to death and taking their money. Player can wreak as much havoc as he likes without progressing through the game’s storyline.”

Raise your hand if you think it’s a good idea to hand this game to an adolescent.

Proponents will argue that games with adult content are now clearly labeled. They say even the most sophisticated games are poor imitations of reality. In addition, playing games develops children’s tensile skills and teaches them multi-tasking.

Somehow there’s got to be a better way to teach kids how to do several things at once while using only fingers and thumbs. And, labeling never works when out-of-touch parents buy the games for their kids anyway.

In addition to violent content, parents need to worry about the amount of time some kids play.

As a teen, my stepson played video games until the wee hours of the morning. The next day, he was tired, cranky and totally unprepared for school. During summer break, it was non-stop gaming. He would stay up all night, sleep all day and repeat.

His mother and I celebrated the day he walked across the stage and was handed a diploma — and it was signed.

Dr. Gentile warns parents in the Pediatrics for Parents article “Simply put, the amount of time spent playing video games has a negative correlation with academic performance. Playing violent games has a positive correlation with antisocial and aggressive behavior.”

Translation: if your kid spends all his time playing video games, his grades will suffer. (Duh.) And, if he plays violent games, he’ll grow unfriendly and abusive. (Duh, again.)

So, if you want your children to excel in school and treat others with kindness and respect, you might want to unplug the Nintendo or Playstation and pry the plastic controller from their little hands.

Or, here’s a better idea. Trade that game console in for a Wii Fit. Your kid will be smarter and nicer. And maybe you can start solving his obesity problem too.