Looking back, why didn’t we take the coronavirus pandemic seriously early on? We had advance warning, both from experts and from witnessing the grievous impact in China and then in Europe. Yet, in addition to the US government’s failure to act, many of us continued life as normal. Even after the alarms sounded more loudly, plenty of people continued to travel, such as the dense spring break crowds that partied on Florida and Texas beaches before they were finally closed.

As the crisis has worn on and backlash against social distancing measures has mounted, some of those same beaches have reopened to large crowds. And now, it’s become increasingly clear that COVID-19 is decimating nursing homes across the country. In Massachusetts alone, there have been 1,316 COVID-19 deaths reported in long-term care facilities as of Thursday; 283 long-term care facilities have at least one case; and 177 have 10 or more cases. These numbers will rise, and yet the response from both the state and federal government as well as the public seems muted and sluggish.

Our initial dismissiveness reflects several quirks of human psychology. People have difficulty imagining how unprecedented events (e.g., future climate change) will affect their lives. In addition, dismissive reactions to the pandemic were driven by specific cultural beliefs so ingrained that we fail to question them: for instance, seemingly benign stereotypes that devalue older and more physically vulnerable people.

Urgency seemed to dim when it became widely believed that only elderly people and people compromised by preexisting conditions were likely to die from COVID-19, while younger and healthier people would be only mildly affected. As former Fox News host Bill O’Reilly said in an interview with Sean Hannity, “Many people who are dying [of COVID-19], both here and around the world, were on their last legs anyway.’’ Clearly that proved wrong. And now, protests demanding the premature lifting of stay-at-home orders implicitly neglect not only what science tells us, but also devalue the many lives now being lost and the future victims the virus will claim. Pervasive biases cause us to react less to some groups’ greater risk.

Contradictory attitudes toward older people partly reflect the subtypes into which we place them. The powerful patriarch still garners respect. But as our research with Susan Fiske shows, even the most common stereotype about elderly people reflects a fundamental ambivalence. Dozens of studies reveal that many societies view elderly people, as well as people with disabilities, as “warm but incompetent.’’ As a result, we like, but do not value or respect, our elders or those with disabilities. They are, in this view, expendable.

But this view is not innate. Some societies greatly value the lives of their older members. As the coronavirus begins to ravage tribal nations in the United States, Nick Martin of The New Republic explained: “It’s hard to overstate the importance of Native elders to their families, tribes, and communities. These are people who fought on the front lines to withstand American assimilation. They fostered our languages and our traditions. They carry with them stories and memories that will fade when they pass, precious fragments of their tribe’s collective story. But more than being living carriers of cultural knowledge, they’re our parents, our grandparents, aunties, and uncles."

In short, the central contradiction is that we profess affection toward older and people with disabilities even as we dismiss them. We see a pair of grandparents with their grandchild in the park and think, “Isn’t that sweet!’’ We go out of our way to help a stranger in a wheelchair. Yet, when times get tough, affection yields to neglect, or worse.

Our research shows that when times are good, there is sustained support (e.g., allocating resources) for older people and people with disabilities. But even then, they receive patronizing treatment that diminishes their autonomy (e.g., the “elder speak’’ that treats older people like simpletons or the over-helping that people with disabilities often experience).

The psychological dynamic shifts when societies face threats. Passive neglect quickly replaces support. In more extreme circumstances, things can get much worse. Although liked but devalued groups don’t normally elicit aggression, when widespread threats cause others to view them as a liability, their lower perceived value puts them at risk

The most extreme example: Before the death camps were built, the Nazis covertly began their killing spree against the elderly and Germans with disabilities. Although motivated, in part, by the belief that “genetically inferior’’ people degraded Aryans racial superiority, the Nazis also invoked economic considerations. They were actively murdered in the name of saving the economy.

We have not seen anyone propose preemptive euthanasia, but some, such as Lieutenant Governor Dan Patrick of Texas, have suggested older people should voluntarily court a premature death to help save the economy. Prematurely ending social distancing to restore prosperity is not the same as actively gassing old and disabled people, but it will ultimately have the same effect, dooming many to die, just in a more random pattern.

By contrast, public efforts to sustain closures and social distancing tend to appeal to the toll the virus has taken on younger, healthier people — the kind of people not “expected’’ to die. Society views these deaths as especially tragic because, quite simply, it values such individuals more. Reports that another nursing home has been devastated elicit little more than a sad shake of the head. As others have noted, imagine how differently we would react if the almost 30 percent death rate in a nursing home in Virginia happened at a children’s day-care center.

Despite the patina of affection for the elderly and people with disabilities, the pandemic has revealed how we inherently devalue them. For example, an anonymous call to police about a nursing home in New Jersey led officials to discover the bodies of 17 residents in a morgue designed to store only four. Some states have not bothered to track coronavirus deaths in nursing homes. Even in the outbreak’s epicenter, New York, it took until mid-April to add people who died in nursing homes to the death count. Like disadvantaged minority groups — who have also experienced a much higher COVID-19 death toll — their deaths elicit less concern. The sister of a disabled resident at a Richmond, Va., nursing home, where at least 45 residents have died of the virus said, “I just know my brother’s fighting for his life. . . . It makes you ask yourself — the disabled and the elderly, are they really getting the service that they deserve, that they need?’’

Our stereotypes make us more willing to play Russian roulette with vulnerable people’s lives while willfully leaving extra bullets in the cylinder. Pervasive biases that some people are more expendable than others led to policy delays and encouraged risky behavior early in the crisis. Unfortunately, the devaluation of those who suffer most from this crisis may lead us to become lax even now that we collectively know better.

Peter Glick is a professor in the social sciences at Lawrence University and a senior scientist with the Neuroleadership Institute. Amy Cuddy is a social psychologist, author of “Presence,’’ and is on the faculty of Harvard Business School Executive Education.