Character complexity and redundancy in writing systems over human history

Abstract

A writing system is a visual notation system wherein a repertoire of marks, or strokes, is used to build a repertoire of characters. Are there any commonalities across writing systems concerning the rules governing how strokes combine into characters; commonalities that might help us identify selection pressures on the development of written language? In an effort to answer this question we examined how strokes combine to make characters in more than 100 writing systems over human history, ranging from about 10 to 200 characters, and including numerals, abjads, abugidas, alphabets and syllabaries from five major taxa: Ancient NearEastern, European, Middle Eastern, South Asian, Southeast Asian. We discovered underlying similarities in two fundamental respects.(i) The number of strokes per characters is approximately three, independent of the number of characters in the writing system; numeral systems are the exception, having on average only two strokes per character. (ii) Characters are ca. 50% redundant, independent of writing system size; intuitively, this means that a character's identity can be determined even when half of its strokes are removed.Because writing systems are under selective pressure to have characters that are easy for the visual system to recognize and for the motor system to write, these fundamental commonalities may be a fingerprint of mechanisms underlying the visuo-motor system.Keywords: writing; reading; redundancy; complexity; letter perception; character recognition INTRODUCTIONWriting systems (such as alphabets) are visual notation systems wherein a repertoire of marks, or strokes, is used to construct a set of characters. Because writing systems are under selective pressure to be easy to read and write, we reasoned that by identifying commonalities underlying how strokes combine into characters in writing systems over human history, we would, in effect, be identifying fundamental properties of the human visuo-motor system. Here, we are interested in measuring two specific fundamental properties of writing systems: character length, which is the average number of strokes per character, and redundancy, which measures how efficiently characters are built out of strokes. Our main result will be that, after examining more than 100 writing systems over human history (table 1), ranging from about 10 to 200 characters, we determined that writing systems have average lengths of approximately three strokes per character and redundancies of ca. 50%, and these values do not vary much as a function of writing system size. In x 4 we will speculate on what this might tell us about the human visuo-motor system.

Economically organized hierarchies in WordNet and the Oxford English Dictionary

“…Many of our other human inventions have been designed-either explicitly or via cultural selection over time-so as to minimize their demands on the brain. For example, writing and other human visual signs appear to have been optimized by cultural selection for our visual systems (Changizi, 2006(Changizi, , 2009Changizi & Shimojo, 2005;Changizi, Zhang, Ye, & Shimojo, 2006). The definitions in the dictionary are not identical to the meanings of words we have in our heads, missing out, for example, on metaphorical associations that may be part of an individual's meaning of the word (see, e.g., Fillmore, 1975;Lakoff & Johnson, 1980, 2003, but it would be surprising if the large-scale organization of the dictionary was not driven in some large part by the organization of our mental lexicon.…”

BACS: The Brussels Artificial Character Sets for studies in cognitive psychology and neuroscience

“…A cross-linguistic study comparing more than 100 alphabetic and nonalphabetic scripts showed that writing systems share a similar number of strokes per symbol, with three strokes per character on average (e.g., Changizi & Shimojo, 2005). Moreover, there is high redundancy within sets (around 50%) reflecting the tendency to re-use the same types of strokes rather than to create new ones.…”

“…This could be sufficient for certain nonlinguistic studies, but it is definitely not valid when the aim is to closely reproduce situations of exposure to natural print. In real writing systems, the number of characters varies from 6 to 180, but only two writing systems (out of more than 100) have less than ten characters, and the average number is 32 (Changizi & Shimojo, 2005). In both sets, we therefore created a number of characters similar to the number of letters in the Latin alphabet (i.e., 24 for BACS-1 and 26 for BACS-2).…”

“…All characters therefore have the same size. Then we selected strokes on the basis of the definition used by Changizi and Shimojo (2005). A character stroke is a pencil stroke ending when the movement slows down to mark an angle or to raise the pencil.…”

Letter processing and font information during reading: Beyond distinctiveness, where vision meets design

“…Changizi et al supported their thesis by finding commonalities in contour configurations across writing systems, nonlinguistic symbols, and natural scenes. In a further study of letter components, Changizi and Shimojo (2005) concluded that writing systems have evolved to balance distinctiveness and uniformity. Parallels between object perception and letter design were also studied by Lanthier, Risko, Stolz and Besner (2009).…”