What Covid Taught Us

When the pandemic upended our lives five years ago today, it gave researchers a rare chance to learn more about who we are and how we live. The entire world changed at once, creating natural experiments everywhere. What happens when sports teams play in empty stadiums? When the government sends people money? When women stop wearing high heels? When children stop going to school?

In many cases, it was impossible to know what caused the specific changes — some aspect of the Covid pandemic or another invisible influence. But the findings demystified several aspects of our world. My colleague Irineo Cabreros and I wrote about them in a story we published today. Here are some highlights:

Crowds help the home team

When sports teams played in empty stadiums, research showed that yes, the fans made a difference: Home teams played worse without them around. They were less likely to win at home and had poorer performances. The effect was smaller for teams already accustomed to smaller crowds. But the home advantage wasn’t just about fans. When the N.B.A. restarted play, the top 22 teams isolated in Orlando, Fla., allowing researchers to study the effects of jet lag. Rebounding, shooting accuracy and wins were all higher among players who hadn’t traveled across time zones.

Virtual doctor visits work …

Telehealth, once uncommon, accounted for half of medical visits early in the pandemic. Mostly, patients and doctors were satisfied with seeing one another online. Telehealth lowered health care costs. It was especially useful for treating chronic illnesses and for psychotherapy. And in some cases, the pandemic revealed, people don’t need to see a doctor at all. The number of patients showing up with mild appendicitis decreased, while the number with complicated appendicitis didn’t change, which suggested that some people who would typically have had surgery recovered on their own.

When it came to learning, remote schooling wasn’t enough. Across the country, in rich and poor districts, and among white, Black and Hispanic students, test scores in reading and math fell. Many students still haven’t caught up. There was learning loss even in countries that had shorter school closures than the United States did. But the data is clear: The sooner children returned to classrooms, even part time, the better they did.

Dolphins talked more

When humans were less active — what scientists call the anthropause — animals began breeding more and traveling farther. Dolphins whistled longer, birds changed their songs, sea turtles laid more eggs. In some places, predators or invasive species arrived. Urban wildlife that had become accustomed to coexisting with humans (and our trash), like crows or raccoons, retreated. It revealed the ways in which humans both threaten and protect the natural world, scientists said.