Mitt Romney: “The human brain shrinks by 20% by the time you're 80 years…”

“I'm not, I'm. I'm not the first one to tell you that. You know, Bill Bryce, Bill Bryson, in his book the Body, he points out that The human brain shrinks by 20% by the time you're 80 years of age. 20% smaller. Just the size of the brain itself. So I basically think people who are 80 and above really should not be running the world or running the country.” (30:17–30:22)

This is an excerpt from a raw transcript. The assertions have not been audited or verified. Tap the video to view the source footage and understand the context.