Even a computer generated avatar!
Joan Straumanis of NSF's Science of Learning Centers program had a neat little slide in her presentation today at the NSE Grantee's meeting at NSF. She says that research in learning shows that if your goal is getting people to learn something:
Expert explanation . . . is not as effective as
Peer explanation . . . which is not as effective as
Self explanation . . . which is not as effective as
Teaching another . . . even when that other is a computer-generated avatar