Peer teaching is not a new concept. It can be traced back to Aristotle’s use of archons, or student leaders, and to the letters of Seneca the Younger. It was first organized as a theory by Scotsman Andrew Bell in 1795, and later implemented into French and English schools in the 19th century. Over the past 30-40 years, peer teaching has become increasingly popular in conjunction with mixed ability grouping in K-12 public schools and an interest in more financially efficient methods of teaching.
Not to be confused with peer instruction—a relatively new concept designed by Harvard professor Eric Mazur in the early 1990s— peer teaching is a method by which one student instructs another student in material on which the first is an expert and the second is a novice.
Cited From: http://www.opencolleges.edu.au/informed/features/peer-teaching/#ixzz2WNdo2SpV