SERIAL POSITION EFFECTS AND DURATION OF MEMORY FOR NONSPATIAL STIMULI IN RATS

Recognition memory for lists of nonspatial items was tested in rats using a nonmatching-to-sample task. The recency effect at short retention intervals disappeared as the interval increased, but primacy did not develop although responding was still above chance up to 2 hr after 10-s sample times. Neither proactive nor retroactive interference was apparent. Rats transferred the nonmatching-to-sample rule to completely novel stimuli. The study failed to replicate the prominent U-shaped serial position curve found in a similar study by P. Reed, T. Chih-Ta, J. P. Aggleton, and J. N. P. Rawlins (1991), for which E. A. Gaffan and D. Gaffan (1992) had found the data less variable than expected. Evidence of primacy in this procedure remains insubstantial.