The Relationship Between Geometric Shape and Slope for the Representation of a Goal Location

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The Relationship Between Geometric Shape and
Slope for the Representation of a Goal Location
in Pigeons (Columba livia)
Daniele Nardi Bowling Green State University
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Apparatus
Top view
Lateral view
Arena
Feeder
Pigeon
Platform
20º
Floor
50cm
Arena
Platform surrounded by curtains
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Apparatus
Arena on a flat surface
Arena on a slope (20º)
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Experiment 1
Acquisition


Slope-related cues added a considerably salient
orienting cue to the geometric shape of the arena
? The task was significantly easier on a slope
Possible factors shape of the arena, slope
inclination.
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Experiment 1
Geometry test

Geometry test
Training
Subjects in the slope condition encoded geometric
shape just like subjects in the flat condition.
Training on a slope did not prevent learning
geometric shape information.
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Experiment 1
Conflict test

Other
Conflict test
Training
Pigeons encoded shape geometry but they were
primarily relying on a slope-based representation
to solve the task.
Possible factors affecting the salience of
geometry/slope slope inclination, arena
shape. Two modular output representations in
guiding behavior
Cheng Newcombe, 2005
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Experiment 2
GEOMTERY SLOPE
GEOMETRY
FLAT CONDITION N 5
SLOPE-HORIZONTAL CONDITION N 5
SLOPE-VERTICAL CONDITION N 5
Geometry test
FLAT
Goal 2 test if the salience of vertical
information influences geometric shape learning
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Experiment 3
Rotation test
Training
uphill
uphill
uphill

downhill
downhill
downhill
Geometric correct
uphill
Mirror image
Rotation test
The novel orientation is COUNTERBALANCED
Near
Far
downhill
Pigeons do not generalize the task to a novel
orientation (replication of Kelly Spetch,
2004) Systematic error to the mirror image
corner Why?
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CONCLUSIONS
Salience of slope information - first study
showing that birds can locate a goal using a
slope gradient - redundant multimodal sensory
activations - implications against the primacy
of geometry for navigation - implications
against view-based strategy for solving geometric
tasks Lack of cue competition between slope and
geometric learning - many indications of an
independent learning of geometry from feature
cues - here geometry is not overshadowed by a
cue that is more salient - new evidence in
support of the geometric module Interactions
between two spatial cues can go beyond
overshadowing and can produce unexpected effects
lack of generalization. Study of associative
learning applied to spatial memory should not be
confined to the usual spatial cues.