Abstract
Using runway training procedure, three experiments examined effects of interrun interval (IRI) shift on serial pattern learning in rats. Series consisted of varying number of 0.045g food pellets given in a goal box of a runway. Groups of rats were trained with 24-10-1-0 or 24-16-10-6-3-1-0 series (Experiment 1), 14-7-3-1-0 series (Experiment 2), and 18-12-6-3-1-0 or 18-7-7-7-1-0 series (Experiment 3), under either short (15-20 s) or long (5-15 min) IRI. In test phases, IRI was shifted from short to long or vice versa. Anticipation of 0 pellet was not disrupted by shortening of IRI, whereas lengthening of IRI eliminated the 0 pellet anticipation of the five- to seven-item monotonic series but did not eliminate that for the four-item series and the nonmonotonic series. These results suggest that rats learn a series with different strategies depending on IRI, pattern length, or structural complexity of a series.
