The Development of Mental Processing integrates several psychological approaches in order to create a more comprehensive theoretical system. This system is tested through a longitudinal study of children 8 to 16 years of age, where findings show that it is ones efficiency at processing information, which has the greatest impact on the development of the working memory. This working memory, in turn, becomes the underlying factor determining individual differences in thinking.

• Study presenting a developing comprehensive theorhetical system and showing its evolution.
  
• Includes commentary by Kurt Fischer and Theo Dawson.
  
• An interesting monograph for both students and researchers about the process of theory creation as much as the study's findings.