Age-related Differences in Processing Speed in Preschool Children

The aim of this study was to assess whether age-related differences in reaction time can be explained satisfactorily in terms of a global age-related differences in processing speed alone. We investigated the age-related differences in simple, discrimination and choice reaction time in 4- to 6-year-old children and young adults using approach proposed by Madden et al. and Ridderinkhoff & van der Molen. This research demonstrates that there are clear age-related differences in processing speed not only between young children and adults but also between three age groups of young children. The use of the regression approach in this study provides further support for the presence of the global age-related differences in processing speed both between young children and adults and between young children of three age groups. The current data also confirmed the results of previous researches that the magnitude of the slowing coefficient decreases with increasing age. However, using transformation method proposed by Madden et al. and Ridderinkhoff & van der Molen we revealed that there are not only global age-related differences but also process-specific age-related differences in processing speed. We assume that the age-related differences in processing speed can be understood in relation to the heterochronicity of child brain development.