Most of us are familiar with the theory that lowercase letters are easier to read than caps because they have a varied contour (ascenders & descenders vs. all letters the same height).
These days, how accepted is this theory? Has there been recent empirical cognitive research that tends to support it or refute it? I see it passed along as fact in many places but perhaps it has quietly gone obsolete, and if so, I would not want to propagate blarney. (Though if you wait long enough, most blarney gets rehabilitated.)