Roger Dooley shares this,
A Princeton study compared student retention of course material presented in both a simple font and more complex fonts, and found that retention was significantly better for the complex font.
Why is this? It appears that the additional effort required to read the complex fonts (also called “disfluent” fonts) leads to deeper processing, and ultimately better recall. The simple font tested was Arial; the complicated ones were Comic Sans Italic, Monotype Corsiva, and Haettenschweiler.