There are only two ways writers can fail to communicate: They either fail to make the reader understand the story, or they fail to understand it themselves. One way to guard against either sounds like “show, don’t tell”, but it’s a little different: Depict key information physically, whether shown or summarized, but not just in dialogue or by making claims about abstract concepts.

Po Bronson & Ashley Merryman’s book Nurture Shock describes an experiment to determine whether violent television shows made kindergartners act more violent. Psychologists observed the playtime behavior of children who had watched different types of television shows. They counted the number of times each child showed antisocial behavior, physical or verbal.

They found that children who watched violent TV shows acted a little more aggressive. But kids who watched educational TV shows acted a lot more aggressive.

They concluded that the kids didn’t put the events together as a story with causal connections. If they watched an episode of a cartoon where the main character acts aggressively through most of the show and then learns to act better at the very end―a common plot in educational TV―then the kids spent most of their time acting like that character acted most of the time. When kids see the character bully the other characters, the bully is having more fun than the rest of the kids, so the children imitate the bully, not the other characters. On seeing the bully apologize at the end, the kids don’t go back and retroactively change how they interpreted her earlier behavior. Kids weren’t learning what the writers wanted them to learn, because they didn’t understand the story the writers wanted to tell.

The psychologists didn’t say, but I suspect it may be partly because the writers told the crucial parts in dialogue, without showing change. Sure, the bully may say she’s sorry. But all you see is the bully being mean, then doing something spectacularly mean, then not being mean anymore. Can a 4-year-old be blamed for not realizing anything important happened there? Or your 20-something-year-old reader, for that matter?

Readers don’t get the message the writer wants to convey when the writer tells one story, but accidentally shows another. For instance, the writers of Superman, Batman, and the other superhero shows and comics of my youth probably didn’t realize that they were teaching me to kill.

Violent solutions have an appealing simplicity and effectiveness. If I’d been president in 1962, I doubt we would’ve gotten through the Cuban missile crisis so successfully. If I’d been a black man in Mississippi in the 1960s, it’s hard to imagine how I could’ve gotten through the decade without getting a rifle and starting to shoot white people.

The allure of violence is widespread. Most political discourse in America doesn’t make sense if you imagine it’s intended to convince people of one view or another. It makes more sense if you assume that the only solution anyone on either side really believes in is to kill everybody on the other side.

Yet all through my youth I was carefully sheltered from violence—more so than my parent’s generation was, who read EC comics and watched war movie after war movie, and were often encouraged by their parents to solve their differences with each other with their fists; and more than the present generation, which has probably seen more gore and violence on TV and in video games by the age of ten than I had when I graduated high school. Instead of John Wayne or Team Fortress 2, we had Batman, Spiderman, He-Man, and other do-gooders who fought bloodless battles with the same villains over and over again. Didn’t this teach us that killing isn’t the answer?

What I remember, when I think about it, is being more and more disgusted with Batman for not just dropping the Joker out a window. They showed, over and over, that the merciful, bloodless code of Superman and Batman was a failure. They always sent the villains back to jail; they always escaped again; more innocent people always died again.

(It wasn’t just comics. It was the American formula for all entertainment for boys. It was like fluoride: in the water, unavoidable).

The writers thought that they were teaching kids to be merciful, as Superman was merciful. They also thought they were teaching compassion towards the villains by showing that they weren’t just interested in money, power, or thrills, but had tragic back-stories that made them hate the hero obsessively. But what they were really teaching kids was this:

1. Problems are made by evil, corrupted people who can never be reformed.
2. Evil people oppose you because they hate you and want to destroy everything you stand for.
3. Good always beats evil in a fair fight.
4. Superman should have dropped Lex Luthor from 30,000 feet in Action Comics #2.

Today’s online first-person-shooters might make kids enjoy violence. I don’t know. But at least these kids learn that violence has risks, and that it’s easier to start a fight than to end it. Video games don’t show kids over and over that the good guys are super-powerful and could easily solve everybody’s problems without anybody innocent getting hurt if they just stopped being wimps and killed all the bad guys. Counterstrike might have lead to school shootings, but Superman led to the invasion of Iraq.

It’s not hard to accidentally show the opposite of what you say. When I read the tidbit from a story a small time author I admire wrote he stated that,a key idea of one specific story was that immortality was a great prize, so giving it up voluntarily was an act of (literal) self-sacrifice. Character A said she wanted to live forever. But what most people saw was that Character A was thousands of years old, still unable to solve her own problems, and desperately unhappy; therefore, immortality is a curse, and giving it to someone else was an act of selfishness, changing the meaning of the story. The story he told didn’t quite match the story he showed.

(And sometimes you embarrass yourself by actually telling the story you subconsciously wanted to tell, instead of the story you thought you wanted to tell. Fred Clark’s ongoing reviews of Left Behind claim that the whole series is a continual exposure of the twisted psyches of its authors that would humiliate them if they weren’t too stupid to recognize it. I realized after writing one of my short stories I did a little while ago that it was a suspiciously-good allegory for something in my own life).

Every time you warp your story world’s reality one way for story purposes—villains are never reformed, or a super-intelligent, godlike entity thousands of years old obsessed with motherhood can’t just adopt—everything connected to that change warps a little bit too, changing the story’s meaning. It’s like laying a warped sheet of linoleum. You can press on the bump in the center and flatten it out, but littler bumps will spread out in all directions.

The bumps will happen in places you didn’t nail down by showing. Showing something makes it true in the story world. Having a character say something doesn’t. If Batman just says that killing the Joker would be wrong, the kid reading doesn’t know if it is or isn’t, even within the story world. Maybe Batman is wrong.

Telling your readers something important is dangerous. It means you didn’t show it, which means it might not be true even within your story.

That may be the main advantage of showing over telling. It isn’t that body language is good and narrative is bad. It’s that things shown are true within that world; things told could be lies.