Eighteen years ago, more than 60% of Americans watched as the worst terror attack ever to occur on U.S. soil unfolded on television — either in real time or in repeated replays.
That up-close view of the murders of almost 3,000 people jolted Americans out of the sense of security they’d enjoyed at least since World War II.
“I think that up until that time, perhaps people were more optimistic or certainly had a sense that it couldn't happen here. Terrorist attacks were something that happened overseas, but not in the United States on our soil,” says Roxane Cohen Silver, professor of psychological science at the University of California, Irvine.
“The concept of fearing violence on a day-to-day basis just wasn't part of the existence of most people in the United States.”
TV viewers said the Sept. 11, 2001 terrorist attack was the all-time most memorable moment shared by television viewers during the past 50 years, according to a 2012 study.
Cohen Silver, who studies the impact of collective trauma, says some individuals with no direct connection to the 9/11 attacks exhibited symptoms that experts had previously assumed were the result of direct exposure to trauma.
“Individuals who watched a great deal of television in the first week after 9/11 were more likely to exhibit post-traumatic stress symptomatology and physical health ailments years later,” she says.
Those symptoms often included anxiety and fear, as well as the onset of physical health ailments such as cardiovascular issues.
“We learned from 9/11 that large-scale events could impact people beyond the directly affected communities, that the events that occurred in New York could impact people in Kansas,” Cohen Silver says. “The second message we've learned from 9/11 was the important role of the media in transmitting that awareness and that potential anxiety.”
Students and others watch live television coverage of the 9/11 attacks on the UCLA campus in Los Angeles, Sept. 11, 2001.
In the 18 years since 9/11, the rise of social media and smartphones has resulted in increased access to images of mass violence. In addition, there are no news editors or other middlemen to weed out potentially disturbing content. The speed with which these images reach people has also escalated.
Young Americans born after 9/11 have grown up in a world where acts of mass violence are increasingly commonplace.
More than 230 school shootings have occurred since 1999, when 13 people were killed at Columbine High School near Denver.
A man cries on Sept. 11, 2001 after witnessing the collapse of the north tower of the World Trade Center in New York City.
Mass attacks continue to occur in places that Americans commonly view as safe spaces, from the 2016 Orlando nightclub attack that killed 49; the 2017 Las Vegas concert shooting where 58 people were killed and hundreds more wounded; to last month’s shooting at a Texas Walmart that left 22 people dead.
“We’re so consumed with new events, you know, current events, hurricanes, mass violence events. And there are many of these that occur, and they're all tragic,” says Cohen Silver. “But the psychological effects of September 11, 2019, cannot be directly linked to the 9/11 attacks without considering all of the rest of the things that have occurred.”
While the average American cannot control the violence around them, they can protect their mental health by not inundating themselves with images of the tragedies, which can be psychologically unhealthy.
"I believe that people can be informed without becoming immersed in the media. There's no obvious benefit to repeated exposure to images and sounds of tragedy,” says Cohen Silver. “And so, once people are informed, I would say to practice caution in the amount of media attention that they engage and the amount of media exposure that they engage in.”