How much can you jam into a human brain? In this segment, Jonah Lehrer tells us the stunning tale of Mr. S., a man whose memory seemed to have no limits. And Dr. Elkhonon Goldberg warns of the dark side of this gift. Then we visit the annual World Memory Championships, to meet expert brain stuffers. Competitor Ron White unveils some of the tricks he uses to memorize long strings of random numbers (hint: envision Albert Einstein riding a roller coaster).

Correction: An earlier version of this piece stated in error that Mr. S. remembered what his editor had assigned all the reporters at the newspaper. In A.R. Luria’s book, there is mention only of Mr. S. remembering his own assignments. We also inaccurately stated the rate at which Mr. S. could recall numbers. The actual rate was 50 numbers in 2.5-3 minutes. We also incorrectly stated that Mr. S. memorized Dante's “Inferno.” In fact, Mr. S. memorized only the first several stanzas. In addition, we depicted details of Mr. S.’s mnemonic performances without making clear that they were based in part on supposition. The audio has been adjusted to correct these facts and clarify our suppositions.