The Cone of Learning - Challenging Conventional Wisdom

Virtually every single teacher will have seen what is commonly known as 'the cone of learning' by Edgar Dale (a US educationalist) and the associated percentages that show 'how' people learn. For those not familiar with the 'cone of learning' I have included an image below: There are a number of variations of Dales work, for example:How we learn:Lecture: 5%Reading: 10%Audio Visual: 20%Demonstration: 30%Discussion group: 50%Practice by doing: 75%Teaching others or immediate application of learning: 90%However, where do these percentages come from? Actually, no-one seems to know. The cone of learning is actually, the 'cone of experience' and was published by Edgar Dale in 1969 and contained no associated percentages. So, where on earth do these percentages come from which people use with such authority on how people actually learn?Well, at first it it appeared that these percentages were publishd in 1967 by a Mobile Oil Company employee who was writing in the magazine, 'Film and Audio-Visual Communications. The employees name was D.G Treichler. Unfortunately, Treichler didnt cite any research relating to these percentages but never the less, many educators have accepted these percentages as fact when in fact, they may actually be just fiction. However, the NTL Institute for Applied Behavioral Science has since laid claim to the percentages, saying that they are based on research in the 'early sixties' but adding that 'we no longer have - nor can we find- the original research that supports these numbers'.Now remember...if you read this blog, you will only remember 10% of it...or will you?