the relationship between geometric shape and slope for the representation of a goal location in...
TRANSCRIPT
The Relationship Between Geometric Shape and Slope for the Representation of a Goal Location
in Pigeons (Columba livia)
Daniele NardiBowling Green State University
Platformsurrounded by curtains
Feeder
Arena 50cm
Pigeon
Floor
Platform
20º
Arena
Top view Lateral view
Apparatus
Arena on a flat surface Arena on a slope (20º)
Apparatus
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.
*
Experiment 1
Task acquisition
0
2
4
6
8
10
12
14
16
18
FLATCONDITION
SLOPECONDITION
Se
ss
ion
s t
o c
rite
rio
n
Geometry test
Geometry testTraining
UPHILL
DOWNHILL
GoalMirrorImage
NearFar
MirrorImage
NearFar
FL
AT
Geomcorrect
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.
Experiment 1
*
0
20
40
60
80
100
Geometriccorrect
Mirrorimage
Near Far
Pe
rce
nta
ge
of c
ho
ice
s
Training
UPHILL
DOWNHILL
GoalMirrorImage
NearFar
Conflict test
UPHILL
DOWNHILL
Slopecorrect
Geomcorrect
MirrorImage
Conflict test
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
Experiment 1
*
Other
0
20
40
60
80
100
Geometriccorrect
Mirrorimage
Slopecorrect
Other
Per
cent
age
of c
hoic
es
FL
AT
MirrorImage
NearFar
Geomcorrect
Geometry test
uphill
downhill
uphill
downhill
flat
FLAT CONDITION
N = 5
SLOPE-HORIZONTAL CONDITION
N = 5
SLOPE-VERTICAL CONDITION
N = 5
GEOMTERY + SLOPEExperiment 2
Goal 2: test if the salience of vertical information influences geometric shape learning
GEOMETRY
Experiment 3
Rotation test
Pigeons do not generalize the task to a novel orientation (replication of Kelly & Spetch, 2004)Systematic error to the mirror image corner… Why?
Rotation testThe novel orientation isCOUNTERBALANCED
*
Traininguphill
downhill
uphill
downhill
uphill
downhill
uphill
downhill
Geometric correct
Mirror image
Near Far
Rotation test
0
20
40
60
80
100
Geometriccorrect
Mirror image Near Far
Per
cen
tag
e o
f ch
oic
es
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.