For some people, the ability to visualize a treasured memory or even a loved one’s face just isn’t possible. New Yorker staff writer Larissa MacFarquhar joins guest host Courtney Collins to discuss a condition that makes it impossible for people to put their thoughts into mental images, the huge effect that has on other parts of their lives and how researchers can use the condition to help study trauma. Her article is “Some People Can’t See Mental Images. The Consequences Are Profound.” Learn about your ad choices: dovetail.prx.org/ad-choices

“Sweet dreams,” we say at bedtime. But why do we dream at all? And what happens when we’re plagued by nightmares? Michelle Carr is director of the Dream Engineering Laboratory in the Center for Advanced Research in Sleep Medicine, an assistant professor at the University of Montreal and a former president of the International Association for the Study of Dreams. She joins guest host Courtney Collins to discuss the sleeping mind, how to move past nightmares to a more restful night and how we can even take control of our dreams. Her book is “Nightmare Obscura: A Dream Engineer’s Guide Through the Sleeping Mind.” Learn about your ad choices: dovetail.prx.org/ad-choices

After the promises of Reconstruction began to wither, Black Americans searched for freedom in radically different locales. Caleb Gayle is a journalist, author and professor at Northeastern University, and he is also a contributing writer at The New York Times Magazine. He joins guest host John McCaa to tell the story of Edward McCabe, who made it his life’s work to set up a Black state in Oklahoma. His book is “Black Moses: A Saga of Ambition and the Fight for a Black State.” Learn about your ad choices: dovetail.prx.org/ad-choices

The U.S. and China may be the world’s current superpowers – but that doesn’t mean they can ignore other countries. Emma Ashford is a senior fellow at the Stimson Center, and she joins guest host John McCaa to discuss the implications of moving to a multipolarity, in which Russia, India and others hold increasing sway over global affairs. Her article “Making Multipolarity Work” was published by Foreign Affairs. Learn about your ad choices: dovetail.prx.org/ad-choices

Advancements in science give hope to those who need life-saving skin grafts, replacements for failing organs – and even for those dreaming of a new head of hair. Science journalist Mary Roach joins guest host Paige Phelps to discuss the myriad of ways researchers are making progress on creating new body parts and why our immune system is the biggest hurdle of all. Her book is “Replaceable You: Adventures in Human Anatomy.” Learn about your ad choices: dovetail.prx.org/ad-choices

From our little fur babies to “Herbie” the car, we imbue the world around us with wonderous human-like qualities. Justin Gregg is senior research associate with the Dolphin Communication Project and an Adjunct Professor at St. Francis Xavier University, where he lectures on animal behavior and cognition. He joins host Krys Boyd to discuss the benefits of anthropomorphism — and the detriments of its polar opposite — dehumanization. Plus, we’ll be introduced to a wide world where we love to see animals and objects as reflections of ourselves. His book is “Humanish: What Talking to Your Cat or Naming Your Car Reveals About the Uniquely Human Need to Humanize.” Learn about your ad choices: dovetail.prx.org/ad-choices

When we clock in on Monday morning, most of us are looking at a 40-hour work week. But what’s so special about 40 hours? Andrew Blackman joins host Krys Boyd to discuss the history of the 40-hour week, how the Great Depression finally presented an opportunity to shrink the working day, and how we might shave off even more hours in our modern era. His article “How Did We Get a 40-Hour Workweek and Has It Had Its Day?” was published in The Wall Street Journal. Learn about your ad choices: dovetail.prx.org/ad-choices

“Life, liberty and the pursuit of happiness” was a radical concept for the Founding Fathers. How did they get there? Walter Isaacson joins host Krys Boyd to discuss how one sentence in the Declaration of Independence set out a promise of America, how Thomas Jefferson, Benjamin Franklin and John Adams wrestled with its crafting, and how we can still use these words as our common values in a polarized nation today. His book is “The Greatest Sentence Ever Written.” Learn about your ad choices: dovetail.prx.org/ad-choices

All those loyalty points you’re racking up at the grocery store, hotels and airlines benefit those companies way more than you. Samuel A.A. Levine is a senior fellow at U.C. Berkeley’s Center for Consumer Law & Economic Justice and he previously served as director of the FTC’s Bureau of Consumer Protection. He joins host Krys Boyd to discuss why newcomers to loyalty programs get priority over long-time customers, the privacy we trade off to get what we think are deals and why we might encounter higher prices anyway. His paper (co-authored by Stephanie T. Nguyen) “The Loyalty Trap: How Loyalty Programs Hook Us with Deals, Hack our Brains, and Hike Our Prices” was published by The Vanderbilt Policy Accelerator and U.C. Berkeley Center for Consumer Law and Economic Justice. Learn about your ad choices: dovetail.prx.org/ad-choices

Newly designed earbuds promise real-time translations right to your ear. But is something lost when we don’t engage with other languages? Ross Benjamin is an award-winning translator of German-language literature. He joins host Krys Boyd to discuss what we miss when we don’t squirm a little in a foreign country and why being less than fluent affects how we pay attention and learn. Plus, we’ll talk about all the beauty we’ll gloss over when A.I. handles the hard parts. His article “The Costs of Instant Translation” was published in The Atlantic. Learn about your ad choices: dovetail.prx.org/ad-choices