Geometric rule learning by Clark's nutcrackers (Nucifraga columbiana).

Abstract

Clark's nutcrackers (Nucifraga columbiana) were trained to search in a location defined by its geometric relationship to 2 landmarks. Two groups were trained to search at different points along the line connecting the landmarks, and 2 groups were trained to find the 3rd point of a triangle, on the basis of either direction or distance from the landmarks. All groups learned and transferred to new interlandmark distances. However, the constant-distance group learned more slowly, searched less accurately, and showed less transfer than the other 3 groups. When tested with new orientations of the landmarks, the birds tended to follow small but not large rotations. When tested with a single landmark, birds in the half , quarter, and constant-bearing groups searched in the appropriate direction from the landmark, but birds in the distance group did not. These results demonstrate that nutcrackers can learn a variety of geometric principles, that directional information may be weighted more heavily than distance information, and that the birds can use both absolute and relative information about spatial relationships. All buried-seed test trials were videotaped. The videotape for each session was played back on an NEC JC-1401 computer monitor connected to a TARGA videographics board and a Panasonic AG-1730

Searching by rules: Pigeons' (Columba livia) landmark-based search according to constant bearing or constant distance.

“…It appears that pigeons had more difficulty localizing the midpoint between the landmarks than determining how far from the landmark array to search. In contrast, Kamil and Jones (2000) found no significant differences between axes in either the constant-bearing or the constant-distance group of nutcrackers.…”

“…By contrast, nutcrackers trained in the constant-bearing condition showed excellent transfer to both the interpolated and extrapolated novel interlandmark distances (Kamil & Jones, 2000). Nutcrackers in the constant-distance condition showed good transfer to interpolated distances but an increase in error for the extrap- olated distances.…”

Beacon training in a water maze can facilitate and compete with subsequent room cue learning in rats.

“…For example, food-storing birds and rats use flexible hierarchies of spatial learning, the expression of which changes with circumstances and previous experience (e.g., Brodbeck, 1994;Kamil & Jones, 2000;Roche & Timberlake, 1998;Shettleworth & Sutton, 2005). Observations of free-ranging rats also support the operation of multiple spatial mechanisms in establishing and using trails connecting burrows and feeding areas (Calhoun, 1962;Leonard & McNaughton, 1990).…”

Memory in Food Caching Animals

“…The birds learned the task readily and searched extremely accurately when tested with new interlandmark distances. Follow-up studies demonstrated that nutcrackers could learn other geometrical rules (Kamil and Jones, 2000), including the use of relative bearings Jones and Kamil, 2001). Comparative studies found that nutcrackers performed these tasks much more accurately than pigeons (Jones et al, 2002;Spetch et al, 2003).…”