Strategy effects on word searching in Japanese letter fluency tests: evidence from the NIRS findings

Strategy effects on word searching in the Japanese letter fluency test were investigated using the Near-infrared Spectroscopy (NIRS). Participants were given a Japanese letter fluency test and they were classified into two types of strategy users, based on analysis of their recorded verbal responses. One group, AIUEO-order strategy users, employed sequential word searching based upon the imagery of the AIUEO-table which they mastered when young, and the other group, semantic strategy users, searched for the next word mainly based on semantic relations. The blood-flow volumes (OxyHb) measured of the AIUEO-order strategy users were greater than for the semantic strategy users in the frontal parts of the brain, and the blood-flow was more active in the right than in the left part of the brain. These different activation patterns suggest that the NIRS might be useful new brain imaging technique for examination of psychological process in verbal behavior.