Ever notice that the tops of capital Os are often slightly higher than other capital letters? Or that the bottom points of Vs are usually lower?
Typographers have known all along what research psychologists have begun revealing about our minds—that the brain has its own idea of what’s correct, despite what sound math, statistics, or geometry might say otherwise.
For example, if an “O” is drawn to the same height as other capital letters, we think it’s too small. So type designers incorporate “overshoot” into letters with rounded shapes, to appeal to the brain’s sense of proportion.
It’s all in the first installment of a blog series on typeface mechanics by Tobias Frere-Jones, designer of Gotham and many other typefaces.