[wookietrader]

As far as I can tell from the abstract (the rest is behind a paywall) this study will not help in the question of causality. By such studies we can not tell whether

  violent games -> aggressive behaviour
 

or just, which probably no one will take into doubt,

  aggressive behaviour -> violent games.

So, nothing new to see here.

[IvarTJ]

Am I misunderstanding this?

"Sustained violent video game play was significantly related to steeper increases in adolescents' trajectory of aggressive behavior over time. Moreover, greater violent video game play predicted higher levels of aggression over time, after controlling for previous levels of aggression, supporting the socialization hypothesis. In contrast, no support was found for the selection hypothesis. Nonviolent video game play also did not predict higher levels of aggressive behavior over time."

They write that they find support for the "socialization hypothesis", presumably meaning that players pick up norms from the violent games.

[lutusp]

> They write that they find support for the "socialization hypothesis", presumably meaning that players pick up norms from the violent games.

Yes, they say that, but the study offers no evidentiary support for that opinion. Scientific papers are not supposed to be soapboxes for the opinions of the researchers, only the careful reporting of scientific results. And the result of this study is that there is a correlation between aggressive behavior and video game play. Correlation is not causation. Aggressive behavior might lead to a preference of video games, or the reverse. This study cannot sort it out. And a study that did sort it out would do it by forcing people to play, or not play, video games, for an extended period. That's unethical and will never happen.

[001sky]

Correlation is not causation

You speak from experience? There is strong orthogonal logic that supports the hypothesis that simulated violence is effective in generating, inducing, and manipulating aggression in human subjects.

viz> http://news.ycombinator.com/item?id=4625843

[lutusp]

>> Correlation is not causation

> You speak from experience?

It's not as though I invented this idea:

http://en.wikipedia.org/wiki/Correlation_does_not_imply_caus...

> There is strong orthogonal logic that supports the hypothesis that simulated violence is effective in generating, inducing, and manipulating aggression in human subjects.

There is no evidence whatsoever to support a cause-effect relationship such as you suggest. If a study were to be designed that could uncover such a relationship, it would violate experimental ethics and would not be funded.

And your link offers no scientific support whatsoever for your claim. It's an opinion piece, not a scientific study. It offers precisely zero evidence in support of its opinions.

[001sky]

That experiment was Vietnam. You need to read its main reference.

[lutusp]

> That experiment was Vietnam. You need to read its main reference.

By your definition, Vietnam was a scientific experiment? This speaks volumes about how you picture science. The plural of anecdote is not evidence.

[jarofgreen]

> Yes, they say that, but the study offers no evidentiary support for that opinion.

Have you actually read the study in full? If your claiming that the study does not in fact prove what the abstract says it does, then you'll need to provide some more details on that.

[lutusp]

> then you'll need to provide some more details on that.

The scientific burden is not mine to show that the article reports a correlation and nothing more, the burden is on the authors to show that that they have demonstrated a cause-effect relationship. And based on their study design, they wouldn't dare -- they have no way to distinguish causes from effects, as you would know if you actually understood the article and the study it reports.

[zerostar07]

Why would it be unethical if people voluntarily agree to participate?

[lutusp]

> Why would it be unethical if people voluntarily agree to participate?

12-year-olds? The study we're discussing examines the behavior of minors. Minors cannot give the kind of consent you're suggesting.

Also, the sort of strictly designed experiments that might turn psychology into a science, are extremely expensive and not likely to be funded. The reason? Research standards in psychology are so abysmally low that a well-designed study would be so expensive by comparison that the granting agencies would refuse to fund it.

[zerostar07]

Still, one would like to test for the opposite (stopping video games -> less aggressive behaviour).

I remember as a kid we played war games outdoors, i think kids have always done that in some ways.

[arethuza]

"as a kid we played war games outdoors"

When I was a kid (70s) our "war games" were quite remarkably violent - I'm surprised that nobody got killed.

These days I watch my teenage son play rugby - which is itself rather violent (although generally very good natured) and from what I can see it is a pretty good sport for teenagers who like playing it (as my son is going to a rugby-oriented school he is lucky, it must be miserable for kids who hate rugby).

[pygy_]

Yes, their evidence sugests a causal relation.

They define socialization/selection in the abstract:

    the socialization (violent video game play predicts aggression over time) 
    versus selection hypotheses (aggression predicts violent video game play over time)

[gojomo]

Unless they're missing some other factor that drives both aggression and the gameplay choices -- a factor other than the "previous levels of aggression" they mention as being a tested control.

Perhaps, some other childhood stressor or failure in coping mechanisms? And if this other factor tends to trigger first, escapism into violent gameplaying, but then later (if unaddressed), actual aggression, I think they could see the "steeper increases in adolescents' trajectory of aggressive behavior" that's reported, even though the gameplaying is just a waypoint or signal rather than cause.

(Under this hypothesis, it's possible the violent gameplaying aggravates the underlying issue, if it delays or prevents other remedies, but it's also possible the gameplaying serves to soften the aggression. You can't really tell from their sequenced relations analysis... you'd want some stronger random-like control on the amount of violent gameplaying.)

[jarofgreen]

> Unless they're missing some other factor

From Abstract: "and a comprehensive set of potential 3rd variables were included as covariates in each analysis".

Sounds like they certainly tried to control for that - you'd have to read the full study to see the details.

[gojomo]

Yes, too bad the full text is behind a paywall. So I haven't read the full study, but I was once upon a time a teenager.

I recall many aspects of my and my peer's psychological lives that would not be easily available to an outside researcher as part of their "comprehensive set of potential 3rd variables".

[droithomme]

> "greater violent video game play predicted higher levels of aggression over time, after controlling for previous levels of aggression, supporting the socialization hypothesis"

[hkuo]

It seems from the abstract that they're not looking for causation between those two but what other factors are involved that can explain the correlation.

[sdoering]

In studies like these you can only look for correlation, not causation. But you can look for other factors, so to eliminate some theories.

here for example the socialization-hypothesis. So it seems, that they have found a way to debunk the theory, that more violent teens tend to play more violent videogames. they controlled for pre-playing aggression-levels, and they monitored the developement of aggression over a longer period of time, to see, if the level of aggression changed (as it seems to do), when playing violent games.

So yes, the can only show a more or less strong correlation between these two factors (and there might be a lot of other factors not controlled for), but they can show, that some other hypothesis does not explain the data.

not more - but not less either.

[pygy_]

In this case, the temporal sequence suggests a causation.

A non-causal association would have to be induced by a confounding factor that first causes teens to play violent video games then to behave aggressively, but never in the other order.

The causal effect is reinforced by the dose effect in the context of this temporal sequence, i.e. the more hours they play per day, the more likely they are to behave aggressively.

[gojomo]

A non-causal association would have to be induced by a confounding factor that first causes teens to play violent video games then to behave aggressively, but never in the other order.

Yes, but not "never in the other order": just more often/strongly in the games-first order.

And I don't find such confounding factors hard to think up for 9th-12th graders: difficult family life; social problems with peers; substance abuse; academic performance pressures; etc.

If a teen were to react to any of these, first, by escaping into violent video games (as a relatively easy temporary mood boost), but then second, with measurable aggression, it would fit the sequential relation seen. But we wouldn't know with any sort of confidence if the violent-gameplaying interim behavior worsened or lessened the eventual aggression.