Chunking, rule learning, and multiple item memory in rat interleaved serial pattern learning

Nonhuman animals, like humans, appear sensitive to the structure of the elements of sequences, perhaps even when the structure relates nonadjacent elements. In the present study, we examined the contribution of chunking, rule learning, and item memory when rats learned serial patterns composed of two interleaved subpatterns. In one group, the Wrst interleaved subpattern was a formally simple sequence, whereas in two other groups the Wrst subpattern was formally more complex, containing 2 or 4 violation elements, respectively. In all groups, the second interleaved subpattern encountered was formally simple. Evidence from the study suggests that rats chunked their interleaved patterns into component subpatterns, that is, they cognitively sorted pattern elements to form chunks based on nonadjacent structural relationships that can be characterized as rules. They also learned interitem associations via traditional discrimination learning to use adjacent elements as compound or conWgural cues for later events in the sequence. Thus, the evidence suggests that rats used chunking, rule learning, and interitem association learning concurrently to master these complex patterns.  2005 Published by Elsevier Inc. One question of signiWcance for animal learning research is whether or not animals are constrained to learn about sequences of events on the basis of pair-wise associations This work was supported in part by the National Institute of Mental Health Grant MH48402 to Stephen B. Fountain. We thank Peggy Ruyak for assistance in conducting surgery and collecting data, and Denise Smith for help with data analysis. * Corresponding author. Fax: +1 330 672 3786. E-mail address: [email protected] (S.B. Fountain). 1