I’ve written here before on how understanding one another is our biggest cognitive challenge, and how the “social brain” theory of Robin Dunbar and others asserts that this challenge is what drove the development of our great big brains. In the short talk and q&a above, writer and former ad man Ian Leslie, whose acquaintance I’ve had the pleasure of making here in London, argues that in essence our brains got big so we could figure out deception amid our complex relationships — and that lying is not a bug or an aberration, but essential to our success as individuals and a species.

He covers some nice ground: why kids lie, for instance; and why politicians lie and why we need them to lie. For instance: “People who can lie a little better to themselves do better in business. And economies stagnate when people are too honest with themselves.” Why? Because you have to lie to yourself a bit to think you can actually succeed at something as difficult and risky as launching a business (or making it as a writer).

For the full story, check out his Born Liars, which elaborates this argument and is stuffed full of interesting studies and good writing. It’s a fun read and a great companion to Robert Burton’s On Being Certain.

Also check out Leslie’s ever-interesting (mostly) political blog, Marbury, and follow him on Twitter.