Serial-position curves in rats: Order memory for episodic spatial events

With the use of a recognition probe procedure, rats were trained to remember serial order of a four- or eight-item list (places on an eight-arm radial maze). The animals displayed a prominent “primacy” and “recency” effect, indicating a serial-position curve. The serial-position curve was more pronounced for the eight-item than for the four-item list. It is suggested that the “primacy” effect of serial-position curves is primarily a function of the utilization of controlled or effortful information processing. In addition, the data suggest a correspondence between animals and humans in the generation of serial-position curves for list learning.