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Interference effects in the spatial memory of seed caching corvids

Jody L Lewis, University of Nebraska - Lincoln


I tested the spatial memory of serially presented locations in Clark's nutcrackers (Nucifraga columbiana). Birds were presented with lists of locations in an open room by offering a buried seed in a sand filled cup at each location, one at a time. Birds were then tested for their memory for each location by opening clusters of cups surrounding the correct location. Accuracy was measured by how many tries the bird required to find the correct location. In chapter 2, I found no evidence of serial position effects, but did find evidence for proactive and retroactive interference after the presentation of two lists of locations. Nutcrackers performed worse on a list whether the interfering information came before (proactive) or after (retroactive) the target list. Furthermore, when items from two lists were located close to each other, nutcrackers made errors by visiting the interfering list locations during recall of the target list. This suggests that the majority of interference in nutcracker memory is due to revisits to depleted locations. Two experiments, presented in chapter 3, were conducted to determine whether increasing the interval between lists or changing the landmark array during study and recall of each list would decrease proactive interference. Increasing the interval did not affect interference, but changing the landmark array eliminated errors made in repeat clusters during recall of list 2. Finally, chapter 4 demonstrates that there was no difference between the performance of nutcrackers and scrub jays (Aphelocoma coerulescens) for their susceptibility to proactive interference in this task. ^

Subject Area

Biology, Ecology|Psychology, Psychobiology

Recommended Citation

Lewis, Jody L, "Interference effects in the spatial memory of seed caching corvids" (2005). ETD collection for University of Nebraska - Lincoln. AAI3176792.