Playing the role of Investigator
In our literature circle discussion tomorrow, as Investigator, I won't do any outside research but I'll try to (1) identify places in Gallagher's book where he draws on other texts and resources (like Harvey Daniels' Literature Circles) and (2) to identify places in our discussion (both f2f and online) where we refer to other works. So, I might interrupt you at times and ask for clarification about where a particular idea or strategy you mention comes from.
One thing I really like about the "specific roles in discussion strategy" is that it pushes us out of our comfort zones a bit. In a discussion, I usually jump right in with questions (discussion director) or pithy quotes I love (literary luminary), so I particularly wanted to try a different role. Although they can challenge us, having specific roles is also safe, in that the role is defined and manageable, we can rely on others to do things we aren't doing, and we don't need to feel dumb because everyone is role-playing. That safety makes Gallagher's metaphor of roles as "training wheels" an apt one for me. College teachers often disdain any form of training wheels, but then they complain their driveways are littered with bruised and bloody student bodies. (that extended metaphor is for you, Jen!)