Studies have shown
that immediately after listening to a 10-minute oral presentation, the
average listener has heard, understood and retained 50 percent of what
was said.
Within 48 hours, that drops off another 50 percent to a final level of 25 percent efficiency.
"...An experiment
conducted with the cooperation of Minneapolis teachers from first grade
through high school. Each teacher involved was asked to interrupt
classes and suddenly ask pupils 'what were you thinking about?' or 'what
was I talking about?'
Results were discouraging but informative. The answers of first and
second graders showed that more than 90 percent were listening.
Percentages dropped in higher grades. In junior high school classes,
only 44 percent of the students were listening. In high school classes,
the average dropped to 28 percent."
http://extension.missouri.edu/publications/DisplayPub.aspx?P=CM150
