The present status of the study on the validity of concurrent verbalization

We reviewed study on the validity of the method of verbal reports. The method of verbal reports gives us detailed information about human cognitive process as compared with observing a sequence of actions, while it is subjected to criticism for the validity as data. Ericsson and Simon proposed a model of verbalization and investigated conditions to keep verbal reports valid. Although a lot of studies quote their model as a base of adopting the method of verbal reports, verification the validity of verbal reports is incomplete because effects of verbalization is not clear. We pointed out that it is necessary to take into consideration kinds of task strategies, effects of trial repetition, effects of task difficulty to examine precisely effects of verbalization. (author)