Interference effects in the memory for serially presented locations in clark's nutcrackers, Nucifraga columbiana.

Abstract

The authors tested the spatial memory of serially presented locations in Clark's nutcrackers (Nucifraga columbiana). Birds were serially presented with locations in an open room. The authors buried a seed in a sand-filled cup at each location and then tested nutcrackers for their memory for each location in the list by using the cluster method. For each item in the list, the authors opened a cluster of 6 holes. Accuracy was measured by how many tries were required for the bird to find the correct location within each cluster. In Experiments 1 and 2, the authors presented 2 lists of locations and found evidence for proactive and retroactive interference. Nutcrackers made errors by visiting the interfering list of locations during recovery of the target list. This finding demonstrates that nutcrackers are susceptible to proactive and retroactive interference during the recall of spatial information.

Serial reversal learning and the evolution of behavioral flexibility in three species of North American corvids (Gymnorhinus cyanocephalus, Nucifraga columbiana, Aphelocoma californica).

“…Clark's nutcrackers (Nucifraga columbiana) are comparatively asocial, but each year, individual birds bury thousands of pine seeds in unmarked locations across their territories, relocating them later by spatial memory (Bednekoff, Balda, Kamil, & Hile, 1997;Tomback, 1998;Vander Wall & Balda, 1981). Because nutcrackers must remember not just where seeds have been cached but also which previous caches have been depleted, their management of spatial memory might be thought to require significant cognitive flexibility Lewis & Kamil, 2006). Western scrub jays (Aphelocoma californica) have a broad dietary niche, making use of a variety of food extraction techniques, and they show a moderate ability to adapt their social systems to suit geographical differences in resource availability (Carmen, 2004;Curry, Peterson, & Lange, 2002).…”

Changing room cues reduces the effects of proactive interference in Clark's Nutcrackers, Nucifraga columbiana.

“…We ran this study in October 2004; 2 months had passed between the end of the interference experiments and the beginning of this experiment. We gave the birds one trial a day (i.e., list) for 4 days to refresh the birds on the list learning procedures (see Lewis & Kamil, 2006) and to acclimate them to the new landmarks. During the 4 days, we tested each bird with a random order of each landmark set twice.…”

“…We studied spatial list learning by serially presenting several locations in an open field and testing the bird’s memory for each location by allowing the bird to choose among the correct location and five other possible locations (i.e., the cluster method; see Lewis & Kamil, 2006). Nutcrackers made more errors when recalling a list of spatial locations if they had previously been tested with a spatial list the same day (Lewis & Kamil, 2006). Despite the nutcracker’s impressive memory abilities (e.g., Bednekoff, Kamil, & Balda, 1997; Balda & Kamil, 1992; Tomback, 1980; Vander Wall & Hutchins, 1983), they are still susceptible to interference in the laboratory like many other nonhuman species such as rats and pigeons (e.g., Cohen, Sturdy, & Hicks, 1996; Grant, 1981; Hoffman & Maki, 1986; Roberts & Dale, 1981).…”

“…Animals make errors by choosing the sample that occurred prior ( N – 1) to the current sample ( N ). Clark’s Nutcrackers are also susceptible to intrusion errors in spatial memory and make more errors within a List 2 cluster when it contained a location that was previously correct during testing of List 1 (Lewis & Kamil, 2006). …”

Memory in Food Caching Animals

“…For example, when black-capped chickadees were presented with three-item lists in an operant associative task, they showed clear primacy and recency effects (Crystal and Shettleworth, 1994). And when Lewis and Kamil (2006) gave Clark's nutcrackers separate lists of locations to remember, they showed clear retroactive and proactive interference effects between the lists. These results raise the question of why such effects are weak in cache recovery but prevalent with other measures of memory performance.…”