Many people will respond to the heart-wrenching images from Monday's deadly attack at the Boston Marathon by feeling that such tragedies are common and they need to make some changes to their daily lives.
Don't do either, cautions Timothy Strauman, a professor of psychology and neuroscience at Duke.
"Tragic and unexpected events such as the Boston Marathon bombing have the effect of disrupting our individual and collective sense of security," Strauman says.
"As terrible as the bombing was, it is still extraordinarily rare and we should not change how we go about our daily lives because of it. That also would be capitulating to the intentions of the perpetrators, which we as a people should always resist."
Strauman adds that tragedies like the explosions in Boston that killed at least three and wounded nearly 200 remind us that "the world is never going to be a completely safe and benign place."
Seeing the heroic actions of first-responders and bystanders can help people when feeling like their personal sense of safety has been disrupted, he adds.
"We know that even if we were to be involved in such an unpredictable event, our fellow citizens would respond with extraordinary courage -- just as we would if we were the bystanders.
"So in the immediate aftermath of this event, we will feel disoriented and disturbed. But we also know that we will continue to survive and thrive as a community and that we will not let our way of life be fundamentally altered."
As of Tuesday afternoon, no one or group had claimed responsibility for the attack along the finish line of the 116-year-old marathon. Authorities also had not announced any suspects.
The bombs used in Monday's attack did appear particularly sophisticated, says David Schanzer, an associate professor of the practice at the Sanford School of Public Policy, and director of the Triangle Center on Terrorism and Homeland Security.
"That might point us toward a home-grown individual, but we don't know if such as person would be from a domestic group or somebody who was inspired by a connection with an international group or ideology," Schanzer says.
While such attacks remain rare, as Strauman noted, Americans will have to continue living with the threat of future attacks, according to Schanzer.
"I'm sure future athletic events will have more people checking bags, more bomb-sniffing dogs, but they can't be made absolutely secure. The risk of terrorism is still small, even after Monday," he says, "but it is one of the risks we unfortunately have to live with in our daily lives."
History professor Martin Miller charted the evolution of terrorism in his book "The Foundations of Modern Terrorism: State, Society and the Dynamics of Political Violence."
He told TIME that since the terror attacks of Sept. 11, 2001, Americans think differently about the dynamics of terrorism.
"I struggle with my students every semester to try (to) get them to understand that there's more to it than the package left under the table," says Miller, who teaches courses on the history of political violence.
He wants his Duke students to understand terrorism in a specific context rather than simply labeling it as an evil act, he told TIME.
"Terrorism is political violence, it is purposeful," Miller says. "It is done by people who have in mind the achievement of certain goals that they think can't be achieved by other means."