[jimbokun]

I vaguely remembered some result about the ideal lecture length, and some quick Googling produced:

http://www.ncbi.nlm.nih.gov/pubmed/7665025

"CONCLUSION: This study shows that a 20-minute lecture was equal to the classic 50-minute lecture in terms of information retained by residents. If future studies confirm this study's findings, medical educators will need to reevaluate the length of lectures to improve efficiency of teaching."

So even more reason to limit the length of time given to people to talk.