Since education is a kind of "conversation" it might be useful to consider the Gricean maxims of conversation.
I will quote an unknown author who has written about Grice on the web page: http://www.nus.sg/Courses/ELL/lsl23.html
We dealt with speech acts earlier in today's lecture and in the previous lecture. We will be dealing today with the cooperative principle, which as some of you should know from your discourse analysis or text and knowledge courses last year, is another pragmatic concept. ... the cooperative principle, which as many of you know, was introduced by the philosopher H.P. Grice.
To Grice and his followers, one reason why what is said in conversational discourse "makes sense," in spite of the missing implicit elements, is due to the cooperative principle, which usually operates between the speakers and listeners in conversational interaction. According to Grice, cooperative behavior in conversation can be described in terms of four conversational maxims:
1. the maxim of quantity, where one tries to be as informative as one possibly can, and gives as much information as is needed, and no more.
2. the maxim of quality, where one tries to be truthful, and does not give information that is false or that is not supported by evidence.
3. the maxim of relation, where one tries to be relevant, and says things that are pertinent to the discussion.
4. the maxim of manner, when one tries to be as clear, as brief, and as orderly as one can in what one says, and where one avoids obscurity and ambiguity.
As the maxims stand, there may be an overlap, as regards the length of what one says, between the maxims of quantity and manner; this overlap can be explained (partially if not entirely) by thinking of the maxim of quantity (artificial though this approach may be) in terms of units of information. In other words, if the listener needs, let us say, five units of information from the speaker, but gets less, or more than the expected number, then the speaker is breaking the maxim of quantity. However, if the speaker gives the five required units of information, but is either too curt or long-winded in conveying them to the listener, then the maxim of manner is broken. The dividing line however, may be rather thin or unclear, and there are times when we may say that both the maxims of quantity and quality are broken by the same factors.
When I was a grad student I thought it might be useful to analyze existing "educational technology" in terms of the Gricean maxims, under the assumption that interactivity is a kind of conversation.
If this is true, then Educational Techechnology that disobeys the maxims should be less effective (less attractive, motivating, user-friendly, understandable, etc.) than software that obeys the maxims.
Since simulating one-to-one human action is extraordinarily difficult, I would guess that even lectures and e-mail discussions would violate the maxims in various subtle ways and therefore be less effective than one-to-one tutoring with a good human tutor.
This would make a good dissertation topic for someone with the right educational background.