NPR/TED Staff

When James Hansen spoke up about climate change in the 1980s, he risked the loss of his job and reputation. But, he says, it was worth it — because he could not be silent about something so important.

Clint Smith is a poet and doctoral candidate at Harvard. As a high school English teacher, he taught his students the dangers of staying quiet and the importance of finding their voice.

After 9/11, Dalia Mogahed saw an increase in negative perceptions of Muslims in the media, so she made it her job to speak up for her faith and fight prejudice with better understanding.

Social psychologist Adam Galinsky studies why it's so daunting to speak up — and what can help. He says the most powerful factor that compels us to take that risk is "moral conviction."

Maysoon Zayid teases herself for all the ways she's different: she has cerebral palsy, she's Muslim, she's Palestinian. By making us laugh at it, she gets us to think about acceptance.

When comedian and TV host Sandi Toksvig came out as gay in the early 1990s, she used humor to recover from the onslaught of vitriol.Today, she says, humor can help bring about social change.

The image of the "sad clown" can seem like a cliche. But for Kevin Breel, it's very real. He describes how he struggled with depression while performing as a stand-up comedian.

Comedian Negin Farsad traveled all over the U.S. to clear up misconceptions about Islam while making people laugh. She calls this form of activism "social justice comedy."

Psycho-economist Sheena Iyengar explains how we can actively use choice as a tool to help us arrive at decisions we can live with.

One choice isn't always better than the other. Philosopher Ruth Chang says, once we realize that, it's easier to embrace the hard work of decision-making.

We often think that our decisions are our own. But Behavioral Economist Dan Ariely explains how our environment — even something as simple as how a question is framed — can affect what we choose.

We assume that our choices come with prepackaged consequences. But author Malcolm Gladwell explains how we aren't simply passive recipients of our decisions.

Sometimes, doctors just don't have the answers. Surgeon Kevin Jones says having the humility to acknowledge this leads to better medicine.

In school, we're taught we should trust science because the scientific method leads to measurable results and hard facts. But Naomi Oreskes says the process of inquiry doesn't end there.

Former Bennington College President Liz Coleman believes higher education is overly-specialized & complacent. She says we need to encourage students to ask bigger questions and take more risks.

When Michael Stevens is confronted with a quirky question, he responsibly searches for the answer and posts it to YouTube — inviting millions of people to follow his journey of discovery.

Trained as a neuroscientist, Eric Haseltine always asks questions. He's identified four concepts that lead to scientific breakthrough. One of them: acknowledging we're not the center of the universe.

Doctors often take a patient's race into account when making a diagnosis--or ruling one out. Professor Dorothy Roberts says this practice is both outdated and dangerous.

Jen Brea's doctors thought her fatigue and neurological symptoms were psychosomatic — but she knew that wasn't quite right. She shares her journey to find the right diagnosis.

Doctors told Jen Brea that her symptoms were psychosomatic, so she filmed herself and turned to the Internet for guidance. She describes how her online community helped her find the right diagnosis.