Dale's Cone of Experience was an attempt by Edgar Dale to organize audiovisual learning experiences from the most concrete to the most abstract, starting with direct, purposeful experiences and ending with verbal symbols.
Dale's Cone of Experience has been grossly misrepresented and changed into a cone of learning pyramid that falsely posits that people remember only 10% of what they read, 20% of what they hear, and 90% of what they do.
