"While multitasking may seem to be saving time, psychologists, neuroscientists and others are finding that it can put us under a great deal of stress and actually make us less efficient."
2008 multitasking study. From the conclusion:
"Our results suggest that interruptions lead people to change
not only work rhythms but also strategies and mental states.
Another possibility is that interruptions do in fact lengthen
the time to perform a task but that this extra time only
occurs directly after the interruption when reorienting back
to the task, and it can be compensated for by a faster and
more stressful working style."
Not phenomenal editing, but gets his point across: based on evidence, Mazur was convinced that lecturing alone wasn't as effective a tool as engaging his students in active learning.