[referring to Moore, 11 Sep 98] Thanks for opening the discussion, and on something very controversial too!
This is a central issue. The idea I am championing is that motivation is a central function of ID and that if it is handled well, then it should not be a problem during instruction. In other words, we need to design motivation "into" our instructional products so that later on the implementor of instruction does not have to find artificial/additional means to get and keep his/her students' attention and interest.
First the problem. I am of the opinion that much of what is taught (especially at secondary school level) is just too boring to be true. Hence the current attraction to technology, problem-based approaches, constructivism, etc.--I believe they are great and that they are reactions to this fundamental problem of poor motivation in classes/courses.
Second the solutions. One is to select the content of instruction based in part on its motivational appeal--in other words be sure that the content is interesting. [See below on issue interactions regarding this]. Another is to situate the instruction--also related to content-- i.e., reach for authenticity, that great ambition of constructivist design. Authentic = interesting/motivating. Another, when these two fail (e.g., with rote learning--the multiplication table for instance), is to design artificial settings such as games... in order to provoke learning despite the constraints.
I talk about motivation again in my chapter in Badrul Kahn's first book. See the introduction online [http://www.nova.edu/~duchaste/motivati-abstract.html] if you wish (I could not put up the whole chapter because of copyright difficulties).
Now, this motivational issue intersects with the political one I point out in Prolegomena, namely the "keep out of content decisions" one. I think it is probably a question of level or grain of decision-making. The decision to teach geometry and what kind of geometry is a political one, whereas decisions about selecting the exact contents and how to represent/introduce them is more along the ID line. I realize this is very vague and that there is a whole gray area in between the two foci. And I guess that is why it is an issue. A very important one.
So, Dave, it is not that it is detrimental for instruction to deal with motivation, only that it shouldn't have. Fundamentally, I think we all want learning to be fun, interesting, captivating--but we have often paid a lot of lip service to that aim, whereas we need to really make it core to ID.