AbstractThree kinds of psychological experiments were performed by a paired‐association paradigm in order to investigate the properties of human memory. The experiments are based on the fan effect where a longer time is required for retrieval with the increase of the number of items associated with an item. In the first experiment, the association pair of meaningless items is used as the object of memory and the retrieval time is measured for the cued recall and recognition tasks. It is seen that while the fan effect is produced in the recognition task, it is not produced in the cued call recall task. In the second experiment, the seman‐tically related association pair (noun‐verb and noun‐noun) is used and the retrieval time is measured in the same way as in experiment 1. As a result it is seen that the fan effect is produced in both recognition and cued recall tasks. The obtained results seem to suggest that a difference exists in the memory structure for the meaningless and semantically related items. It is also suggested that there is a difference in the memory strategy based on the meanings. In the third experiment, the association pair is used where a verb and a noun are associated with the same noun. As a result of the cued recall task, it is shown that the verb is easier to be recalled than the noun. This will be accounted for by assuming that a kind of case structure exists in the