Some days, it's hard to be optimistic. But cynicism -- the idea that people are inherently selfish, greedy and dishonest -- is making humanity lonelier and more divided, says psychologist Jamil Zaki. In this episode of TED Business, we are revisiting fascinating research on cooperation, empathy and trust, as Zaki makes the scientific case for optimism and shows us how to break out of the cynicism trap. Stay tuned after the talk to hear Jamil Zaki and our host Modupe Akinola delve into the high cost of cynicism.