Source: 1979 Instructor Training Course, Instructor Guide Series, Mine Safety and Health Administration, Education and Training Directorate, Feb 1979
Where was it found?4: Hathitrust.org
Search Term: “10 percent of what we hear”
What was found? A reference to the "Cone of Experience" followed by "...we retain only about 10 percent of what we hear, but up to 90 percent of a simulated experience."