The Science of Typography by Ellen Lupton
This article was written by designer and writer Ellen Lupton which details the different ways in which science has explored the typographical world. For example, at one point she discusses studies where specific elements of typography, such as line length, kerning, point size, etc., were explored separately, but Lupton writes about how this is actually pretty inaccurate/inconclusive since some or all the elements included in typography interact with each other inseparably. She covers other topics as well, like font preference and its affect on readers or judgement of efficiency with concerns to line length. This might be an interesting avenue to pursue concerning the primer portion of the PPP project.