Examining the advantage of a live instructor vs. video in a laboratory study

Learners often anecdotally report preferring live instructors to videotaped lectures, but few controlled comparisons exist, and none have been conducted for foreign language learning. College students experienced a single foreign language lesson in an unknown foreign language, Samoan, either from a live instructor or from a videotape of the same lesson. Learners in different classroom sessions were asked to watch passively or act out commands following a Total Physical Response (TPR) lesson plan. Learners who received the lesson from a live instructor scored better on a vocabulary test (average 92% correct) than did those who saw a videotape of the same lesson (79% correct). Acting out commands also facilitated learning (88% correct), compared to viewing the lesson passively (82%). What accounts for the superior learning from the live instructor? Our classrooms had 20 students on average, so the instructor had few opportunities to reinforce individual learners with eye contact, gestures and facial express...