Experimental studies on media violence dating all the way back to the 1960s have shown what consistent result?

Experimental studies on media violence dating all the way back to the 1960s have shown what consistent result?

Media violence is a causal risk factor for aggressive behavior.

Media violence is correlated with aggressive behavior, but is not a direct cause.

Watching media violence can actually help reduce aggressive behavior, by allowing people to vent their aggressive feelings safely.

There haven't been experimental studies going back that far