A ROCKING chair that persuades elderly people to tell stories about their childhood will help to preserve valuable oral history, according to Jennifer Smith of MIT's media lab. She developed the interactive rocking chair because she regretted not having a way of recording all her grandmother's family tales. "When she died we lost all her stories with her," Smith says.

In Smith's system, the elderly person sits on a rocking chair in front of a large screen displaying a life-size, graphic image of a little girl. She tells a story of her own and then asks the person in the rocking chair questions about their life.

In tests, Smith noticed that people's rocking patterns tended to change when they finished a story: "Some people come to a stop, while others speed up," she says. So an accelerometer on the back of the rocking chair monitors movement, feeding information back to ...