There are two research paradigms in the area of serial-order memory. One typically uses serial recall (accuracy), and the other comparative judgment (reaction time) for measuring serial-order memory. Spontaneous subgrouping is commonly observed in the recall serial-position function in the form of multiple bowings. However, comparative judgment with a reaction time measure produces a single-bowing function. Researchers adopting these two approaches have opposing views on the form of the structure of serial-order memory with the former favoring a hierarchical, and the latter a unidimensional structure. The present study confirmed the above hypothesized relation between the two measuring procedures and the two different patterns of serial-position functions. It was suggested that a serial recall involves retrieving absolute position information, whereas a comparative judgment involves retrieving relative position information, and that subgrouping serves a facilitating function for the former, but may actually impede the latter process.
