Rats were runway trained on each of two 3-trial series of reward outcomes.
The series are labeled XNY and ZNN, for which X represents a trial that was
rewarded with Noyes pellets and N represents a trial that ended with no re
ward. Units of distinctively flavored breakfast cereals served as reward on
trials labeled Y and Z. One group (Floor) had each series occur with a cor
related runway floor, either smooth and black or rough and white. For a sec
ond group (Memory), the floor cue was uncorrelated with series. Animals in
both groups learned to approach the goal rapidly on the ist trials of the 2
series and slowly on the 2nd trials, but only Group Floor learned to diffe
rentiate the 3rd trials of the series. These results recommend a view of se
rial learning that emphasizes the role played by information about the ordi
nal position of series items.