Learning pyramid

The earliest such representation is believed to originate in a 1954 book called Audio-Visual Methods in Teaching.

[1] A pyramid model was supposedly developed by the National Training Laboratories Institute in the early 1960s, on its main campus in Bethel, Maine, for which the original, internal research is said to have been lost.

NTL's model generally used the following divisions:[1] Criticism emerged on early versions of the model such as Edgar Dale's Cone of Experience.

[3][4][5] Critics reported inconsistencies between the pyramid of learning and research.

[1] The NTL learning pyramid study being lost, the field largely stands on an unknown methodology of unknown quality, with unknown mitigation of influential parameters such as time, population tested, etc., making the original study's results untrustworthy.