Memory often plays tricks with our understanding of the world. We are absolutely sure that we left the car keys on the counter or that a particularly bad storm happened in the spring of 1983 and not in the autumn the year before. It is a well-established neuroscientific fact that memory is often unreliable and subject to priming, mistakes, and erroneous recall. The saying about “good old days” and imperfect memory has been attributed to many people and the Harvard University psychologist Steven Pinker used it in his 2018 book Enlightenment Now! to explain why we repeatedly underestimate progress in the world.

I distinctly remember the snowy winters of my childhood, growing up in southern Sweden. Every Christmas, my sister and I would play in the snow, build igloos and snowmen, and marvel at the Christmas lights. Except, it turns out that these memories are confused and inaccurate. When Swedish meteorologists looked at the local weather over the last 100 years, they noted that my region sees snow at Christmas only about once every five or ten years. Indeed, since 1981, only a single record exists of a Christmas Eve more than 10 centimeters deep in snow.

When we endure another Christmas in slush and mud, we recall these pristine winters of our childhood and blame our unusually bad luck, climate change, or some other handy explanation for why nothing today seems at great as it once was. I have clear memories of snow and clear memories of Christmas – they just did not happen simultaneously. Of course, we never consider that our memory is playing tricks with us. While trivial, my Christmas story shows that scattered memories of the past can be turned into rosy retrospections of things that never happened.

Most Americans think that homicides have increased in the last few decades, while the real picture is one of a drastic decline. Britons believe that income inequality has exploded in their country. In reality, on most metrics, income inequality is lower than it was in the 1990s. When asked what share of total household wealth is owned by the top 1 percent, people’s guesses are almost three times too high (59 percent versus the real figure of 23 percent).

On teenage pregnancy, the public’s misperception is even worse. Americans routinely estimate that the share of women aged 15-19 who give birth every year is about one-in-four, implying that every teenage girl has a child at some point in her upper teens. The true figure is close to one-in-fifty.

According to a YouGov poll last year, between 21 percent and 45 percent of respondents across the Western world thought that climate change “likely” or “quite likely” will make the human race extinct. At the same time, both the absolute numbers and the proportion of people dying from natural catastrophes like storms, floods, droughts, or wildfires has plummeted over the last century – and that includes all kinds of natural disasters (such as earthquakes and tsunamis) not just the ones that climate change may have worsened.

Put differently, our understanding of the state of the world is not simply plagued by ignorance. Were that the case, people would err randomly in both directions. Instead, we are actively misinformed about the state of the world, routinely underestimating the progress that the world has made and overestimating how great the world was when we were young.

In his 2020 book Open, the Swedish author Johan Norberg discusses deceptions that feelings of nostalgia create. When asked to identify the good old times, people tend to name the decade in which they came of age. Norberg notes that humans, having invented writing, “didn’t take more than two centuries before [they] started writing about how difficult life is now and how it must have been so much easier in the past.” He wrote,

“if you happen to think we have uniquely difficult problems today, with a more rapid pace of life, corrupt rulers and unruly youngsters, don’t trust your feelings. Every generation has thought the same. Every generation has interpreted its struggle with the human predicament and the difficulty of relationships as a sign that things have become worse since a supposedly more harmonious time in the past.”

The question of progress, observed Steven Pinker, is not a matter of optimism or pessimism. Rather, it is a matter of “calibrating our understanding of the world to empirical reality.” Almost everything we can measure – life expectancy, child mortality, starvation, poverty, nutritional inadequacy – is unfathomably better today than it was 50 years ago, 100 years ago, or 200 years ago.

Sure, there are and always will be dips in the charts, like the increased number of murders in New York and Kansas City this year, the reversal of poverty eradication caused by the COVID-19 pandemic, the occasional civil war, or instances of deforestation on our increasingly green planet. But the overwhelming trend is toward improvement.

The Danish researcher Bjørn Lomborg noted in his 2020 book False Alarm that “the scientific facts are left behind because the narrative feels true.” Yet the former U.S. president Barack Obama was surely right when he wrote in 2016 that “if you had to choose any time in the course of human history to be alive, you’d choose this one.”

This is the key contradiction of our time: scanning the long arc of human history, we have never had it better. Yet we don’t think that we are better off. We are depressed and afraid. We are overwhelmed by the latest terrible news broadcast on television. But, well-informed people should be guided by facts, not misplaced nostalgia for the past that never was.