HIV is a serious problem in the DR Congo, and aid agencies have flooded the country with free and cheap condoms. But few people are using them. Why? “Reformed marketer” Amy Lockwood offers a surprising answer that upends a traditional model of philanthropy. (Some NSFW images.) (Recorded at TEDGlobal 2011, July 2011, in Edinburgh, Scotland. Duration: 4:17.)

[ted id=1228]

Watch Amy Lockwood’s talk on TED.com, where you can download it, rate it, comment on it and find other talks and performances from our archive of 1,000+ TEDTalks.