It has long been known that many Mongoloid groups generally have higher IQ scores than Caucasoids, but the reasons for this difference have not been explained. As the authors point out "Intelligence is a multidimensional and hierarchical edifice" which involves both "general" processes which co-ordinate information processing across many domains of thought, as well as "specialized" processes which affect only particular mental tasks, involving e.g., verbal, spatial, or quantitative reasoning.
Mental processing is affected by both genes and environment, and these differ between Greeks and Chinese, as well as between most Caucasoids and Mongoloids in general. For example, Chinese words are shorter than those of Indo-European languages spoken by most Caucasoids, whereas Chinese students have to learn a logographic, picture-based writing system. These differences may affect mental processing, e.g., because "shorter" Chinese words may be stored more easily, whereas more space is required to short the more "complex" logograms of the Chinese writing system.
The article provides three important conclusions. First, the architecture of mental processing is the same in both Greeks and Chinese, involving essentially the same mental processes and organization. In other words, Greeks and Chinese think "the same". Second, the Greeks and Chinese show no difference in the general factor of mental processing which is used across different thought domains. Rather, the difference between the two groups is limited to areas requiring visuo/spatial processing:
Thus, we suggest that this advantage is related to the massive visuo/ spatial practice that they receive in learning Chinese writing. This claim is based on three findings. First, this advantage only slightly generalizes to other realms, where there is equivalent practice or minimal visuo/spatial processing. Second, the two cultural groups have about the same number of visualizers until the third grade; with increasing education, which differentiates the two cultures in the mastering of complex visual information more than in any other aspect of the curriculum, visualizers become many more among the Chinese. Third, with time, Greeks, gradually acquire compensating strategies, even if relevant practice is not sufficient to transform them into visualizers. As a result, their differences from the Chinese tend to decrease with increasing age in the visuo/spatial domain and to disappear in some other domains, such as quantitative reasoning.
The idea that the Chinese logographic system (as well as other similar systems used by other Mongoloids, such as the Koreans or Japanese) represents a type of "mental doping", improving visuo/spatial performance at an early age -if it is confirmed- represents an important victory for those who believe in the significant effect that culture has in mental development, and a further nail in the coffin of the theory that human groups differ from each other in mental processing due to innate genetic factors.
PS: The finding that Greeks do not differ from Chinese in g further discredits Richard Lynn's assessment of Greek IQ, which -together with much of the data in his book- is based on massaged data.
Intelligence (Article in Press)
The architecture, dynamics, and development of mental processing: Greek, Chinese, or Universal?
Andreas Demetriou et al.
This study compared Greeks with Chinese, from 8 to 14 years of age, on measures of processing efficiency, working memory, and reasoning. All processes were addressed through three domains of relations: verbal/propositional, quantitative, and visuo/spatial. Structural equations modelling and rating scale analysis showed that the architecture and developmental patterning of the various processes are basically the same in the two ethic groups. The Chinese clearly outperformed the Greeks in all tasks addressing visuo/spatial processing, from processing efficiency through working memory and reasoning, but neither in g nor in processes where the two groups have equivalent experience. This advantage was associated to the massive practice in visuo/spatial processing that is required to learn the Chinese logographic writing system. The implications for general theory of intelligence and intellectual development are discussed.