Why are letters and other human visual signs shaped the way that they are?
Caltech researchers argue that the shape signature for human visual signs was selected for ease of reading, at the expense of writingIn a new study forthcoming in the May 2006 issue of The American Naturalist, Mark A. Changizi and his coauthors, Qiang Zhang, Hao Ye, and Shinsuke Shimojo, from the California Institute of Technology explore the hypothesis that human visual signs have been cross-culturally selected to reflect common contours in natural scenes that humans have evolved to be good at seeing.
"[We] analyzed one hundred writing systems, Chinese characters, and non-linguistic visual signs, and found that these very different types of human visual signs possess a similar shape structure," explain the researchers.
Comparing human visual signs to natural scenes, the researchers demonstrate a high correlation between the most common contour combinations found in nature and the most common contours found in letters and symbols across cultures. For example, contours resembling an "L" or "X" are more common in both human visual signs and natural scenes than anything resembling an asterisk (*).
The researchers also examined motor and visual skills and the shapes that are easiest to see and form. They make a strong case that the shape signature for human visual signs is primarily selected for reading, at the expense of writing.
Founded in 1867, The American Naturalist is one of the world's most renowned, peer-reviewed publications in ecology, evolution, and population and integrative biology research. AN emphasizes sophisticated methodologies and innovative theoretical syntheses--all in an effort to advance the knowledge of organic evolution and other broad biological principles.
Mark A. Changizi, Qiong Zhang, Hao Ye, and Shinsuke Shimojo "The structures of letters and symbols throughout human history are selected to match those found in objects in natural scenes," The American Naturalist 167:5.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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