Talk Like Ted: The 9 Public-Speaking Secrets of the World's Top Minds

Chapter 7 discusses the hard time limitation for TED Talks, 18 minutes per presentation, and why that is the ideal length. Exceeding this time can lead to information overload, hindering ideas’ transfer and comprehension. It is almost always better to analyze one’s message and condense it down to its most impactful core information. This is because listening is a mentally taxing activity despite being relatively passive. All cognitive processes place silent demands on the mind and body. Active listening requires constant absorption and retention of information. Overloading the “cognitive backlog” of the audience risks frustrating them or provoking anger. The brain quickly becomes fatigued, as sustained listening and learning demand considerable energy. Just as one might feel exhausted after a day of starting a new job or hours of studying, a long lecture will eventually cause the audience to lose focus: “Eighteen minutes is thought-provoking. Three hours is mind-numbing” (188). Gallo recommends incorporating regular breaks every 10 minutes with stories, videos, or demonstrations if speaking for longer than 18 minutes is necessary.

Roughly 18-20 minutes is the best length for a presentation because it strikes a balance. Shorter, and you might not provide enough information.