The Physiology of Reading
Layout that facilitates natural eye movements improves reader comprehension. According to Colin Wheildon, author of, Type & Layout: How typography and design can get your message across--or get in the way, American children are taught to begin reading at the top left corner and work their way across the page from left-to-right until they reach the bottom right corner.
Any design working against this principle may frustrate readers. For example, if you place the headline in the middle of the page, readers will have to return to the top before they can begin reading the body text, which contradicts natural eye movement.
In Wheildon's research, sixty-seven out of 100 test subjects reported good comprehension on layouts that supported natural eye movement, while only 32 readers reported good comprehension on those that disregarded eye movement. (42).