Learn about the treadmill’s torture device origins. Then, author Melanie Peffer explains why biology is everywhere.

Learn about new research into the implicit attitudes people have in close relationships with others (and more) from Vivian Zayas, Director of the Personality, Attachment, and Control Laboratory at Cornell University.

Learn about why opposites don’t really attract; the “propinquity effect”; and when and why we started using last names.

The extremely rare blood type is shared by only a handful of people on Earth.

Captains Keith Colburn and Sig Hansen from the award-winning documentary series “Deadliest Catch” share some surprising science lessons from the fishing world. Plus: learn about the psychology behind “sour grapes.”

Learn about whether reading computer code is the same to your brain as reading another language; and a personality trait that could be key to lasting romance. Then, play along at home as we test your podcast knowledge in this month’s edition of Curiosity Challenge trivia.

Learn about microvacations, a trick for actually using your vacation days even when you’re super busy; the science behind why darkness is actually faster than the speed of light; and why sand is one of the most valuable resources in human civilization — and why we’re running out of it — with some help from Vince Beiser, author of “The World in a Grain: The Story of Sand and How It Transformed Civilization.”

Learn about why rainy days make you sleepy; why the “Great Unconformity” is one of the biggest mysteries in geology; and the problematic amount of energy it takes to power AI — along with a potential solution. Plus: how do you pronounce "Colorado," anyway?

Learn about stem cell “mini brains” that grew eyes and how the FDA prevented an epidemic of birth defects in the 1960s.

Learn about Ivan Pavlov’s dogs, and why you might not know them as well as you thought. Then, learn about the three types of perfectionism that are ruining your life. Plus: if the universe is expanding, then what is it expanding into?

Learn about why social media may not be as bad for mental health as we thought; why the Streisand effect says censoring information will probably backfire; and why tailgating at the light won’t get you through any faster.

Learn about how to tell whether a life hack is worth trying from a special guest: Professor Joseph M. Reagle Jr., author of the new book “Hacking Life: Systematized Living and Its Discontents.” You’ll also learn why there’s no such thing as a “reverse microwave” for cooling.

In this podcast, Cody Gough and Ashley Hamer discuss the following stories from Curiosity.com — and learn about the science of stretching from Get-Fit Guy of Quick and Dirty Tips — to help you get smarter and learn something new in just a few minutes:

Learn about the special way riding a bike is stored in your memory; the crocodile paradox; and the smell of fresh rain.

Learn about how men and women remember pain differently; how to measure how mindful you are; and a theory about alien life and the laws of physics.