Hank gives us a summary of a strange new calculation, which estimates the total body mass of all the humans on earth.

Is it possible that overfishing, super germs, and global warming are all caused by the same thing? In 1968, a man named Garrett Hardin sat down to write an essay about overpopulation. Within it, he discovered a pattern of human behavior...

Architecture can bring people together, or divide them -- witness the skyscraper, costly, inefficient, and only serving small portions of the community. At TEDxPortofSpain, Mark Raymond encourages city governments to let go of their old...

This week in the journal Nature Communications, scientists report a way to use fossilized shark teeth to figure out where different shark species, including megalodon, stood in the web of life. And last week in the journal Scientific...

The path to better food is paved with data, says entrepreneur Erin Baumgartner. Drawing from her experience running a farm-to-table business, she outlines her plan to help create a healthier, zero-waste food system that values the...

What is the best voting system? Voting seems relatively straightforward, yet four of the most widely used voting systems can produce four completely different winners.

Aliens - Are We Looking in the Wrong Place?

Artist Aaron Koblin takes vast amounts of data -- and at times vast numbers of people -- and weaves them into stunning visualizations. From elegant lines tracing airline flights to landscapes of cell phone data, from a Johnny Cash video...

Most spiders are solitary creatures, but a few species group up instead, creating giant colonies where they live and hunt together.

What if we could diagnose some of the world's deadliest diseases by the smells our bodies give off? In a fascinating talk and live demo, biologist James Logan introduces Freya, a malaria-sniffing dog, to show how we can harness the...

Some people think that being a fighter pilot and a parent means that you will have a household full of daughters - but does the data back that up?

Most animals keep their poop chutes on the opposite side of their body from where they eat. But that doesn’t mean it’s always the case, and bryozoans are great examples of how creative you can get with where you put your anus.

So last week we talked about what special interest groups are and how they influence the political system, and today we’re going to focus on why we even have them in the first place. As to avoid getting too cynical, we’re going to focus...

A pioneer in research on play, Dr. Stuart Brown says humor, games, roughhousing, flirtation and fantasy are more than just fun. Plenty of play in childhood makes for happy, smart adults -- and keeping it up can make us smarter at any age.

We need to change how we prescribe drugs, says physician Daniel Kraft: too often, medications are dosed incorrectly, cause toxic side effects or just don't work. In a talk and concept demo, Kraft shares his vision for a future of...

Some birds fly in V shapes because it has many benefits, but other birds fly in clumps instead. Why would they do that?

There's a job out there with a great deal of power, pay, prestige, and near-perfect job-security. And there's only one way to be hired: get appointed to the US Supreme Court. But how do US Supreme Court Justices actually get that honor?...

Today, artificial intelligence helps doctors diagnose patients, pilots fly commercial aircraft, and city planners predict traffic. These AIs are often self-taught, working off a simple set of instructions to create a unique array of...

Social entrepreneur Bernhard Kowatsch shares real-life examples of how a business approach focused on accelerating tech (like a blockchain-supported way to bring food to refugees or a machine that fortifies flour at small mills in...

Hank discusses some new research that studied what makes us unhappy with ourselves and with other people, focusing on homophobia and consumerism.

What can you do to build a better world? Sharing stories from her pioneering career dedicated to tackling poverty, Jacqueline Novogratz offers three principles to spark and sustain a moral revolution. Learn how you can commit (or...

In this video Paul Andersen explains how immune individuals in a population give the entire group a herd immunity. Concepts of immunity, vaccines, basic reproduction number, and herd immunity threshold are discussed.

Sheena Iyengar studies how we make choices -- and how we feel about the choices we make. At TEDGlobal, she talks about both trivial choices (Coke v. Pepsi) and profound ones, and shares her groundbreaking research that has uncovered some...

Introduction to probability density functions.