I have been teaching on-line for American Military University since 2008. During that time I have had to take many professional development courses about how people learn.
There are those who learn by sight (visual learners), some by touch (kinesthetic) and those who learn by sound (audio). The best way to impart education is by a combination of senses to appeal to the widest group of learners and reinforce the message.
Apparently this concept is not lost on Iran as noted in a NY Times article from August 27, 2017, “Iran Retools Its Propaganda With Rap Videos”(See: http://nyti.ms/2iHiBDF; which is also the photo source).
Iran now also seems to believe that chanting is not nearly as powerful as rapping and the You Tube is mightier than the sword seem to be corollaries as well.
The article notes that the raps don’t appeal to everyone, but there doesn’t seem to be any question that they are effective for the target group. Terrorists typically target young people between 18 and 26. (see Huffington Post at: http://bit.ly/2wT5xkP).
Appealing to multiple senses and personifying the message are proven techniques for education and marketing. Our adversaries are very capable of adapting. As technology advances, removing yet more barriers to mass communication, MISO/PSYOP will have to continue to adapt as well.