Difference between a unmanaged switch and a managed switch

I felt that if i asked here i would get a least a few points of view on this question. i was recently told by my CCNA teacher that regualr unmanged switch lack the capability of "learning" where devices are on a network as compared to a cisco or a managed switch. Is he pulling my leg or something because if thats the case then could someone tell me the point of adding a unmanaged switch over a managed switch (besides the cost factor). I trust my teacher and i know he knows his stuff ( he works for BMW) but this statement has changed the way i look at networks in general....any thoughts ladies and gents.