The present paper reviewed some of psychological studies published during the twentieth century. The paper was divided into two main parts ; change of framework and review of studies. In the section of change of framework, three basic theories were introduced; behaviorism, cognitive constructism, and socio-cultural constructism. It was emphasized that these changes were not all-or-nothing but progressive process. In the next section, typical investigations under each theory were reviewed. Drill practice and learning hierarchy were main topics in behaviorism. In cognitive constructism main three investigations such as solving process of word problem, developmental change on understanding fractions, and ratio concepts were reviewed. Experimental instructional interventions were also introduced which would be one of future research paradigm. In social-cultural constructism, studies on informal mathematics which children acquirred through everyday life were reviewed.
Constructing scales with sufficient reliability and validity and establishing causal relationships between psychological constructs are methodologically most important aspects to conduct correlational studies in educational psychology.Through reviewing articles recently published in the Japanese Journal of Educational Psychology and its international counterpart, the Journal of Educational Psychology, several problematic features are discussed.In order to facilitate validation of scales and appropriate use of causal modeling, the importance of theoretical elaboration of constructs and abundant information for validation is emphasized.A property of Japanese research style generating hypotheses rather than testing them is evaluated, since it is suitable to treat the complex character of psychological constructs and scales purported to measure them.