Why does a cold pool feel warmer the second time you dip your toes in? Why does a safecracker run his fingers over sandpaper? Why do Mediterranean cultures touch each other more than Scandinavian cultures? Would it be great -- or not so great -- if you were unable to feel physical pain? Why does stubbing your toe have different sensations through time? And what does any of this have to do with cuddle puddles, NBA players bumping chests, or puppies sleeping in dog piles? Today’s episode is a love story about our sense of touch: what it is, how it works, and why it plays such a critical role in our lives.

Could you instantaneously learn to fly a helicopter -- not by practicing, but instead by uploading instructions directly to your brain? What would society do if children no longer had to go to school? And what does any of this have to do with suntan booths, nanorobots, or what a cowboy on a hill is not able to see? Join Eagleman to learn about the possibility of modifying the microscopic structure of your brain and leapfrogging education. What are the possibilities, the caveats, and the unexpected complexities?

From the brain’s point of view, what is the self? How do 30 trillion cells come to feel like a single entity? Does the "self" of a blind person include the tip of her walking stick? How flexible is our sense of self? And what does any of this have to do with psychedelics, trauma, synchronized swimmers, religious rituals, cheerleaders, or why soldiers across time and place love to march in lockstep? Join Eagleman for this week's episode of surprises about how the brain computes the self.

Presumably we're not going to solve the problem of conflict between groups of people -- but what would better conflict look like? And what does that have to do with brains, the spread of homo sapiens, social media recommender algorithms, tribalism, intellectual humility, or the Iroquois Native Americans? Join this week's episode with guest Jonathan Stray -- a conflict researcher -- for an episode about brain science, war, empathy, outgroups, and how we might do better.

Can you become conscious inside a dream? Can a researcher convey information to a dreamer, and can the dreamer find some way to answer back? Does 10 seconds inside a dream equal 10 seconds in real life? Could taking a drug inside a dream give you a placebo effect? Can you prompt your brain like a large language model? And if so, what would you pose to your unconscious brain? Join David Eagleman and guest Jonathan Berent to discover the what, why, and how of lucid dreaming.

Why do brains dream, and why are dreams so bizarre? Why doesn't your clock work in your dreams? And even though you spend much of your working day looking at your cell phone and computer – why do they almost never make appearances in your dream content? Is dream content the same across cultures and across time? Are dreams experienced in black & white, or in color? Are dreams the strange love child of brain plasticity and the rotation of the planet? What is the relationship between schizophrenia and dreaming? In the future, will we be able to read out the content of somebody's dream? Join Eagleman this week to learn why and how we spend a fraction of our sleep time locked in different realities, swimming in plots which aren't real but which compel us entirely nonetheless.

Why do we spend 1/3 of our lives in the strange doppelganger state of sleep? Can we die from a lack of sleep? How long is it possible to keep yourself awake (and why does the Guinness Book of World Records no longer track that)? Why are some people night owls and some morning larks? What does any of this have to do with lightless underground caves, or with the length of a day on Mars? Join this week's episode to learn everything you've ever wanted to know about sleep and what your brain is actually doing during this time. This is the first of a 3-parter: next week we'll dive into dreams, and the week after that into lucid dreams.

Could you get convicted of a crime based on your brain activity? Are brain scan lie detectors accepted in court, or would that count as illegal search and seizure? And what does this have to do with your mouth getting dry, the orbits under your eyes getting hot, and your voice constricting when you deceive? Join Eagleman to dive into the fascinating topic of whether societies can use technology to figure out whether a person is telling the truth -- and under what circumstances we would even want to go there.

What is depression? Why are brains able to slip into it? Is depression detectable in animals? Do animals have options beyond fight or flight? And what does any of this have to do with measuring depression medications in city water supplies, reward pathways in the brain, the prevalence of tuberculosis, and zapping the head with magnetic stimulation? Join today's episode with David Eagleman and his guest -- psychiatrist Jonathan Downar -- for a deep dive into the brain science behind depression and what new solutions are on the horizon.

Do our visual systems see in frames like a movie camera or instead analyze the world continuously? Why do you see multiple hands when you clap under yellow street lamps? How did Hollywood launch from the question of whether all four legs of a galloping horse come off the ground at once? And what is the very surprising thing that happens if you stare at your ceiling fan for a long time while it turns? This week’s episode is about visual perception -- and a series of eye-opening revelations about how the brain takes in information from the world.

Can a person be declared legally dead even though he is very much alive? In December of 2010, why did a number of families choose to pull their loved ones off life support just before the new year? How do doctors decide when you've died, and how is it different from how lawyers decide? How is death a process rather than an event? What does any of this have to do with getting buried alive, your family's religious beliefs, or whether a head stays alive after the guillotine? Join Eagleman and guest Jacob Appel, an emergency room psychiatrist and head of ethics, for an episode about the science and the questions about death -- including who's domain it is to call it, and where this is all heading.

Who is the most disappointed medalist at the Olympics? How do brains simulate what might have been? How can you get your kid to wear a jacket in the cold? What if you had to face more successful versions of yourself? And what does any of this have to do with why menus should be shorter, why empires divide, and why you should always put yourself in the shoes of future people? Join Eagleman to learn the capstone secrets of mental time travel, and what these have to do with the emotions of regret and relief.

Why are people who can't remember their past also unable to picture their future? Why do we get so anxious about the world changing around us? What should you advise the president if we find ourselves at war with extraterrestrials? And what does this have to do with Wayne Gretzky, or the Greek goddess of memory, or hitting a bottle to get ketchup onto your French fries? Join this week's episode to find out about one of the most important things brains do: simulations of possible futures.

How do billions of neurons store your home address, your ability to ride a bike, and the history of your life? How does memory work in the brain, and how is it different from the way a computer stores information? And what does any of this have to do with the Happy Birthday song, squirrels hiding acorns, bards memorizing epics, or people who cannot forget any of the events of their life? Join Eagleman to learn how and why your brain continually time travels to previous moments.

What role will AI play in the future of fake news and misinformation? What does this have to do with our brains’ internal models, with voice passwords, and with what Eagleman calls "the tall intelligence problem"? And why does he believe that these earliest days of AI are its golden age, and we are quickly heading for a balkanization? Join for today's episode about truth, misinformation, and artificial intelligence.

What is the future of misinformation on the internet? Is it possible that the invention of the internet has improved access to truth? What does any of this have to do with the Oxford English Dictionary, Soviet agriculture, liberation technology, Kenyan elections, Barbra Streisand's house, and Twitter revolutions? Join Eagleman for a surprising foray into the thorny forest of truth in the age of the internet.

We all worry about fake news. But is misinformation and disinformation really new? Join Eagleman for a deep dive into the past, present, and future of truth. Why do cameras not tell us what we think they do? What should we not forget about pamphleteering? And what does this have to do with agriculture in the USSR, or book banning in America, or dog whistles, or apps that only tell facts? And why is it so hard to understand the viewpoints of millions of brains at once? This week's episode is the first of a three-parter -- and today we tackle truth in the media.

Why are our brains so wired for love? Could you fall head over heels for a bot? Might your romantic partner be more satisfied with a 5% better version of you? How does an AI bot plug right into your deep neural circuitry, and what are the pros and cons? And what will it mean when humans you love don’t have to die, but can live on in your phone forever? Join Eagleman for a deep dive into relationships, their AI future, and what it all means for our species.

Is it always harder to teach an old dog new tricks? Why is an older person slower to learn a new language but able to learn new faces easily? Why does Arnold Schwartzenegger have an accent but Mila Kunis doesn’t, even though neither spoke English as a child? Why is there a correlation between how tall a person is and how much salary they're likely to earn? What would it mean to say that you are born as many people but die as a single one? This week's episode dives into surprises about brain plasticity and why your flexibility changes throughout your lifetime.

What does the insanity defense mean in a court of law? And is there such a thing as temporary insanity? Is the twinkie defense a real thing? Can someone use premenstrual syndrome as a defense? And what does the legal wrestling around insanity tell us about the differences between brains: yours and other people’s, or even yours one day and yours the next day? How does law comport with science, and how are they sometimes like two people with quite different ways of looking at the world? Join to find out what happened to Andrea Yates, how the legal system deals with mental illness, and so much more.