How long are Americans sad and angry about mass shootings? Four days.

As overwhelming as the feeling is now, the available evidence suggests that it will fade into the background within about four days. This means we have four days in which to act on it. Four days to take steps that might help prevent the next Uvalde or Sandy Hook or Parkland or Columbine massacre before we move on, before we return to the immediate concerns of our own lives — and before the urge to take on an intractable problem loses the emotion that can fuel momentum.

I came to this conclusion after working with a unique daily survey conducted by Gallup. Nearly every single day from 2008 through 2017, Gallup interviewed a national sample of Americans, asking them their opinions and perceptions about a variety of issues. Gallup also asked about their emotions on a given day: Had they felt happy or sad the day before? Were they angry or smiling? Trends in the data show a remarkably consistent pattern. Almost every day, between 10 percent and 25 percent of Americans reported feeling sadness the previous day. What immediately stands out when these feelings are plotted onto a graph is the tall, anomalous spike in the middle — on Dec. 15, 2012, to be precise. That day, nearly 40 percent of respondents reported feeling sadness the previous day, more than double the percentage on a typical day. The number of respondents who said they felt angry was less dramatic but still significant: 20 percent, vs. 12 percent on a typical day. One day earlier, on Dec. 14, a young man had entered Sandy Hook Elementary School in Newtown, Conn., and killed 20 children and six adults before killing himself.

The poll respondents were not primed to think about the massacre that had taken place in Newtown and give their opinion of the incident. They were simply asked whether they felt angry or sad or happy the day before the interview.

The Parkland teens started something. How can it become a social movement?

The survey’s value is the window it opens into the way this kind of event weighs on our minds, the collective process of grieving that we all went through then — and are going through again, right now.

Crucially, the survey also reveals when these events fade in importance from our minds. The troubling reality is that it doesn’t take long. Days after the Sandy Hook mass shooting, Americans’ reports of sadness and anger returned to their normal levels. This doesn’t mean we forgot about the shooting or no longer cared. It just means that we returned to our lives, that the horror of what had happened had moved away from the forefront of our consciousness even as the sadness and anger lingered in the background.

In a study published last year, Yinzhi Shen and I gathered data on all mass shootings from 2008 through 2016 to test whether Sandy Hook was an anomaly. We found that it was, in the sense that it affected the emotions of the entire country. But other than Sandy Hook’s reach, the pattern I noticed afterward was replicated when we used more refined methods to identify the causal impact of all mass shootings on the emotions of Americans. We found that the most horrific mass shootings with the most victims generate the largest impact on Americans’ emotions, and that the effect of mass shootings is felt most acutely in the cities and towns in which they occur, then fades quickly as the geographic distance between the incident and the survey respondent widens. We found that respondents who identify as Democrats have a larger emotional response to mass shootings than those who identify as Republicans — but, critically, Republicans also report higher levels of sadness and anger in the aftermath of mass shootings, even if their response is more muted than that of Democrats.

But the impact of mass shootings on the emotions of respondents lasts for only a few days, and then it is gone, indistinguishable from the longer time trend. This isn’t true for everyone, of course — the groups that have mobilized against gun violence in the aftermath of Sandy Hook, Parkland and other tragedies have done heroic work, facing off against the full force of the gun lobby. But the survey finding may provide a hint about why these episodes of uniquely American horror have not translated into widespread changes in legislation designed to prevent the next mass shooting or the thousands of “routine” shootings that destroy American lives, families and communities every year. Research has shown that mass shootings lead to an increase in the number of gun-related bills introduced at the state level, but with few exceptions, they tend not to lead to the passage of legislation designed to confront gun violence. In fact, the sick reality of our gun politics has led to the opposite: In Republican-controlled state legislatures, mass shootings are associated with a large increase in legislation designed to loosen gun restrictions.

America is turning against guns

To be clear, there is no evidence of a causal connection between Americans’ emotional response to this kind of incident and the behavior of state or federal legislators. But the pattern of policy responses to mass shootings suggests a link. In the days after the latest mass shooting, politicians express their outrage, their thoughts and prayers, and some put forth new proposals to finally confront the problem with meaningful legislation. A few days pass, and the raw emotions we are all feeling dissipate, even if we’re reluctant to admit it. As the attention of the nation shifts, that legislation stalls, and the organized, well-funded forces that favor guns over children’s lives flex their muscles.

For those who would turn the painful emotions of this moment into action, they have four days. There are models for ways that states can create basic requirements to make it harder for violent people to acquire guns. And, yes, formidable forces have mobilized to make sure these models don’t spread beyond states such as Massachusetts and Connecticut. But the anger and sadness most of America is feeling right now can be a driving force behind political and social movements for change. The right tells us that now is not the time to politicize the latest mass shooting. If policymakers want to harness these emotions and turn them into policy, however, they have only a couple more days to act.