America continues to be afflicted by violence. In the aftermath of terrorist attacks and mass shootings, the focus is often on trauma. And for good reason. Exposure to such extreme harm ruptures the lives of individuals in the surrounding community and broader society. Yet within the tragedy exists a glimmer of hope: Viewing how others respond in the wake of a violent attack can inspire us to help others.  Our research shows that the way people remember past altruistic acts in the aftermath of trauma can actually influence their willingness to act altruistically in the future.

An emerging line of research, done in collaboration with Dan Schacter and Liane Young, suggests that memory can be used to enhance prosocial decisions and behavior to help someone in the lab. Experimentally increasing prosocial responses raises the intriguing possibility that how helping events are encoded and remembered following terror attacks may influence subsequent helping. To more directly examine this question, we investigated how the way that we represent and remember helping events following the Boston Marathon Bombing may be related to subsequent prosocial responses toward victims.

Two bombs exploded during Boston’s 2013 marathon. Hundreds were injured. And hundreds more rallied to help. In the immediate aftermath, runners, spectators, and first responders selflessly put themselves in harm’s way to help the injured victims. These heroic acts gave rise to vivid images, seared in people’s memory. People who recalled helping-related events in greater detail also reported engaging in helping behaviors several months later. Individuals with more detailed helping-related memories reported higher rates of blood donations and of volunteering for, and donating to, Boston-based charities. The findings are correlational. Thus, it is possible that people who are more intrinsically altruistic are also more likely to remember past altruistic behavior. However, future research might prompt a subset of observers to systematically recall helping events in vivid detail following attacks and subsequently examine whether their helping behavior increased. Such an approach would not only inform memory research, but would also have implications for public policy, mass media coverage, and charitable fundraising efforts.

These findings build on prior research highlighting the memorability of traumatic events, with implications for development of possible memory-based interventions in promoting moral behavior. Seminal research in the 1970s on public trauma and memory found that the assassination of President John F Kennedy and related events produced “flashbulb” memories, memories that are seemingly recalled with unusual vividness and intensity. Memories for such traumatic events can shape our personal identities and predict posttraumatic stress reactions. Following 9/11, there has been heightened interest in understanding how public violence and terror attacks give rise to flashbulb memories. Cognitive and affective scientists studying memory, such as William Hirst and Elizabeth Phelps, have made great progress in understanding how the sensory details, emotional grip, and one’s confidence in the accuracy of these highly negative memories change over time. In the aftermath of terror attacks and other disasters, however, comes a wave of altruism that memory researchers have previously overlooked: altruism born of suffering.

Humans have always had a capacity for malicious violence—some of our earliest tools were weapons. While we, as species, have become historically less violent, foreign and domestic terrorism does not seem to be coming to an end any time soon. As a result of the increased lethality and accessibility of destructive technology (e.g., explosives, semi-automated firearms, and chemical weapons), cultural friction, and ubiquity of mass media coverage, vivid memories of attacks and their aftermath will continue to be seared into our minds.

But the same mechanisms that support remembering violent and traumatic aspects of these events can also give rise to vivid memories of extraordinary altruism. It seems navigating towards a more altruistic future may depend, in part, on remembering and being inspired by our collective past.