@Clanad
I'm puzzled as to why American fiction is so obsessive about emotions, what with Spock/Data/Tuvok type characters, exploring what it is to either lack them or, as Data was able to do, have selected emotions programmed in.
McGuffin isn't the right word for this (I believe that to be something central to the plot, not a pace-modifying side-issue) but the idea seems to be to simultaneously express the thought that human emotions are some kind of obstacle to intellectual achievement and something that the human characters use to best effect, arriving at solutions which the de-emotionalised characters would either overlook as a possibility or dismiss out of hand. Thus the whole subject is explored, for our edification.