ISSN : 1229-0718
The purpose of this study is to examine developmental change in the speed of cognitive processes and the factors controlling it. Processing speed develops substantially during elementary school years and approaches the level of adults' during adolescence. This trend is also observed in the studies examining developmental functions of various cognitive processes: Processing speed develops in similar pattern across different tasks. This change was described well by exponential functions with a common decay parameter. In addition, children's processing speed increases linearly as a function of adults' processing speed: correlation between children's processing. speed and adult's processing speed was greater than .90. Age-related differences in cognitive processes are attenuated by approximately 70 % to 90 % when the variance associated with one measure of processing speed is eliminated. These results suggest that development of processing speed is controlled by some general mechanism.