TED Talks Daily (HD video)

Is there an equation for intelligence? Yes. It’s F = T ∇ Sτ. In a fascinating and informative talk, physicist and computer scientist Alex Wissner-Gross explains what in the world that means. (Filmed at TEDxBeaconStreet.)

As the world's cities undergo explosive growth, inequality is intensifying. Wealthy neighborhoods and impoverished slums grow side by side, the gap between them widening. In this eye-opening talk, architect Teddy Cruz asks us to rethink urban development from the bottom up. Sharing lessons from the slums of Tijuana, Cruz explores the creative intelligence of the city's residents and offers a fresh perspective on what we can learn from places of scarcity.

We're all familiar with satellite imagery, but what we might not know is that much of it is out of date. That's because satellites are big and expensive, so there aren't that many of them up in space. As he explains in this fascinating talk, Dan Berkenstock and his team came up with a different solution, designing a cheap, lightweight satellite with a radically new approach to photographing what's going on on Earth.

When Esta Soler lobbied for a bill outlawing domestic violence in 1984, one politician called it the "Take the Fun Out of Marriage Act." "If only I had Twitter then," she mused. This sweeping, optimistic talk charts 30 years of tactics and technologies -- from the Polaroid camera to social media -- that led to a 64% drop in domestic violence in the U.S.

Maya Penn started her first company when she was 8 years old, and thinks deeply about how to be responsible both to her customers and to the planet. She shares her story -- and some animations, and some designs, and some infectious energy -- in this charming talk.

Animal behavior isn't complicated, but it is complex. Nicolas Perony studies how individual animals -- be they Scottish Terriers, bats or meerkats -- follow simple rules that, collectively, create larger patterns of behavior. And how this complexity born of simplicity can help them adapt to new circumstances, as they arise.

McKenna Pope's younger brother loved to cook, but he worried about using an Easy-Bake Oven -- because it was a toy for girls. So at age 13, Pope started an online petition for the American toy company Hasbro to change the pink-and-purple color scheme on the classic toy and incorporate boys into its TV marketing. In a heartening talk, Pope makes the case for gender-neutral toys and gives a rousing call to action to all kids who feel powerless.

When she became the attorney general of New Jersey in 2007, Anne Milgram quickly discovered a few startling facts: not only did her team not really know who they were putting in jail, but they had no way of understanding if their decisions were actually making the public safer. And so began her ongoing, inspirational quest to bring data analytics and statistical analysis to the US criminal justice system.

2013 was a year of hype for MOOCs (massive open online courses). Great big numbers and great big hopes were followed by some disappointing first results. But the head of edX, Anant Agarwal, makes the case that MOOCs still matter -- as a way to share high-level learning widely and supplement (but perhaps not replace) traditional classrooms. Agarwal shares his vision of blended learning, where teachers create the ideal learning experience for 21st century students.

Humanity's fine-tuned sense of fear served us well as a young species, giving us laser focus to avoid being eaten by competing beasts. But it's less wonderful when that same visceral, body-hijacking sense of fear kicks in in front of 20 folk-music fans at a Tuesday night open-mic. Palms sweat, hands shake, vision blurs, and the brain says RUN: it's stage fright. In this charming, tuneful little talk, Joe Kowan talks about how he conquered it.

Every cell in the human body has a sex, which means that men and women are different right down to the cellular level. Yet too often, research and medicine ignore this insight -- and the often startlingly different ways in which the two sexes respond to disease or treatment. As pioneering doctor Paula Johnson describes in this thought-provoking talk, lumping everyone in together means we essentially leave women's health to chance. It's time to rethink.

“If you really want to know a people, start by looking inside their bedrooms," says Shereen El Feki, who traveled through the Middle East for five years, talking to people about sex. While those conversations reflected rigid norms and deep repression, El Feki also discovered that sexual conservatism in the Arab world is a relatively new thing. She wonders: could a re-emergence of public dialogue lead to more satisfying, and safer, sex lives?

What kind of robots does an animator / jazz musician / roboticist make? Playful, reactive, curious ones. Guy Hoffman shows demo film of his family of unusual robots -- including two musical bots that like to jam with humans.

Luke Syson was a curator of Renaissance art, of transcendent paintings of saints and solemn Italian ladies -- serious art. And then he changed jobs, and inherited the Met's collection of ceramics -- pretty, frilly, "useless" candlesticks and vases. He didn't like it. He didn't get it. Until one day … (Filmed at TEDxMet.)

Sheryl Sandberg admits she was terrified to step onto the TED stage in 2010 -- because she was going to talk, for the first time, about the lonely experience of being a woman in the top tiers of business. Millions of views (and a best-selling book) later, the Facebook COO talks with the woman who pushed her to give that first talk, Pat Mitchell. Sandberg opens up about the reaction to her idea, and explores the ways that women still struggle with success.