TED Talks Daily (SD video)

What motivates us to work? Contrary to conventional wisdom, it isn't just money. But it's not exactly joy either. It seems that most of us thrive by making constant progress and feeling a sense of purpose. Behavioral economist Dan Ariely presents two eye-opening experiments that reveal our unexpected and nuanced attitudes toward meaning in our work. (Filmed at TEDxRiodelaPlata.)

Your smartphone may feel like a friend -- but a true friend would give you a smile once in a while. At TED2013, Keller Rinaudo demos Romo, the smartphone-powered mini robot who can motor along with you on a walk, slide you a cup of coffee across the table, and react to you with programmable expressions.

At age 12, Freeman Hrabowski marched with Martin Luther King. Now he's president of the University of Maryland, Baltimore County (UMBC), where he works to create an environment that helps under-represented students -- specifically African-American, Latino and low-income learners -- get degrees in math and science. He shares the four pillars of UMBC's approach.

Trivia whiz Ken Jennings has made a career as a keeper of facts; he holds the longest winning streak in history on the U.S. game show Jeopardy. But in 2011, he played a challenge match against supercomputer Watson -- and lost. With humor and humility, Jennings tells us how it felt to have a computer literally beat him at his own game, and also makes the case for good old-fashioned human knowledge. (Filmed at TEDxSeattleU.)

3D printing has grown in sophistication since the late 1970s; TED Fellow Skylar Tibbits is shaping the next development, which he calls 4D printing, where the fourth dimension is time. This emerging technology will allow us to print objects that then reshape themselves or self-assemble over time. Think: a printed cube that folds before your eyes, or a printed pipe able to sense the need to expand or contract.

There is a corruption at the heart of American politics, caused by the dependence of Congressional candidates on funding from the tiniest percentage of citizens. That's the argument at the core of this blistering talk by legal scholar Lawrence Lessig. With rapid-fire visuals, he shows how the funding process weakens the Republic in the most fundamental way, and issues a rallying bipartisan cry that will resonate with many in the U.S. and beyond.

Imagine an electric vehicle that can get you to work -- or anywhere in a six-mile radius -- quickly, without traffic frustrations or gasoline. Now imagine you can pick it up and carry it with you. Yes, this souped-up skateboard could change the face of morning commutes.

One afternoon, Kees Moeliker got a research opportunity few ornithologists would wish for: A flying duck slammed into his glass office building, died, and then … what happened next would change his life. [Note: Contains graphic images and descriptions of sexual behavior in animals.]

When two people are trying to make a deal -- whether they’re competing or cooperating -- what’s really going on inside their brains? Behavioral economist Colin Camerer shows research that reveals just how little we’re able to predict what others are thinking. And he presents an unexpected study that shows chimpanzees might just be better at it than we are. (Filmed at TEDxCalTech.)

In the Masai community where 13-year-old Richard Turere lives, cattle are all-important. But lion attacks were growing more frequent. In this short, inspiring talk, the young inventor shares the solar-powered solution he designed to safely scare the lions away.

Mark Shaw demos Ultra-Ever Dry, a liquid-repellent coating that acts as an astonishingly powerful shield against water and water-based materials. At the nano level, the spray covers a surface with an umbrella of air so that water bounces right off. Watch for an exciting two-minute kicker.

Our bodies and homes are covered in microbes -- some good for us, some bad for us. As we learn more about the germs and microbes who share our living spaces, TED Fellow Jessica Green asks: Can we design buildings that encourage happy, healthy microbial environments?

Composer and conductor Eric Whitacre has inspired millions by bringing together "virtual choirs," singers from many countries spliced together on video. Now, for the first time ever, he creates the experience in real time, as 32 singers from around the world Skype in to join an onstage choir (assembled from three local colleges) for an epic performance of Whitacre's "Cloudburst," based on a poem by Octavio Paz.

Today we know the molecular cause of 4,000 diseases, but treatments are available for only 250 of them. So what’s taking so long? Geneticist and physician Francis Collins explains why systematic drug discovery is imperative, even for rare and complex diseases, and offers a few solutions -- like teaching old drugs new tricks.

As a child growing up in North Korea, Hyeonseo Lee thought her country was “the best on the planet.” It wasn't until the famine of the 90s that she began to wonder. She escaped the country at 14, to begin a life in hiding, as a refugee in China. Hers is a harrowing, personal tale of survival and hope -- and a powerful reminder of those who face constant danger, even when the border is far behind.