Americans cannot but be dismayed by mounting evidence that excessive violence on television screens may lead to aggressive and perhaps even violent behavior on the part of children and teenagers watching it. A new report prepared by the National Institute of Mental Health finds the nation's research community agreeing - after a decade of accumulated evidence - that there is a strong correlation between televised violence and at least short-term aggression:
''Television can no longer be considered as a casual part of daily life, as an electronic toy. Research findings have long since destroyed the illusion that television is merely innocuous entertainment.''
The question is whether and when parents will become aroused enough to do something about the problem.
Young people would be the first to balk at turning television into just an ''educational'' institution, devoid of gripping drama and adventure. And there are probably few adults who, when asked, would not look back with some nostalgia to those Saturday movie matinees of years back, when they sat transfixed through the derring-do of Buck Rogers and Hopalong Cassidy, or the pell-mell cartoon antics of Tom and Jerry.
The difference, of course, is that the Saturday matinee was just that - one day a week in a setting where fantasy prevailed. Television, which instantly combines reality and fantasy, is quite a different medium. It is more immediate, constantly accessible, and therefore more impressionable.
Broadcasters would thus seem to have a special responsibility to refrain from featuring excessive violence and to provide programming that helps uplift young people even as it entertains. Yet the sad fact is that the only regularly scheduled network daytime children's program today - as was the case ten years ago - is Captain Kangaroo. And that program has now been moved to an earlier, and shorter, viewing time.
On Saturday mornings, cartoon offerings, many of them admittedly clever, have virtually replaced the human characters of the early days of television. There is no Sky King, no Annie Oakley - no real-life role models, no popular heroes or heroines. With the exception of public television, and some occasional specials for young people and Walt Disney shows, network TV is still failing to provide wholesome entertainment for young people.
In light of the violence and sensationalism so often found in prime-time programming, parents are amply justified in taking stock of what their children view - as well as helping to determine exactly which shows can be watched. Unfortunately, by and large they are not doing so now. The report issued this week found that ''parents do not seem to restrict the amount of time their children spend in front of the television set'' nor prevent them ''from looking at certain programs.''
It is hard to understand how adults would neglect so dominant an influence on their children's lives. To be sure, not all TV violence leads to destructive behavior, nor is it clear that negative effects are long-lasting. But surely parents should wish to protect their own children from imbibing such harmful images - which are self-destructive to the child and potentially injurious to society as well.
And what of the broadcast industry? There remains a need for greater integrity and social conscience in programming. Steps of progress can be seen here and there. But it is clear that a fundamental change in attitude will not come without heightened public pressure on the networks and advertisers - by such groups as the National Citizens Committee for Broadcasting - to clean up their act and offer more creative programs aimed directly at young people. Parents should be aware that action by such groups in the past has had good results.
In the final analysis, the public will have the television it tolerates.