TY - JOUR

T1 - Minimization of modal contours

T2 - An essential cross-species strategy in disambiguating relative depth

AU - Forkman, Björn

AU - Vallortigara, Giorgio

N1 - Funding Information: Acknowledgements We wish to thank Marie Haskell for helping with the experiment, Lucia Regolin for commenting on the manuscript and Marina Rugger and Daniele Zavagno for the drawing of Figure 1. The study was supported by the British Ministry of Agriculture, Fisheries and Food. The experiments complied with the Home Office regulations of the UK.

PY - 1999

Y1 - 1999

N2 - Two chromatically identical patterns, a diamond and a ladder, were shown on a computer touchscreen. Domestic hens were reinforced for pecking at the pattern that was the highest up on a grid that provided pictorial depth information, i.e. on the pattern that to a human appears as being the furthest away. Every tenth trial was a non-rewarded probe trial with the two patterns partially overlapping. In the absence of other cues depth stratification can occur on the basis of a minimization of interpolated occluding contours. In humans the diamond is usually perceived to be in front of the ladder because shorter interpolated contours are needed to account for the occlusive effect of the diamond on the ladder. The hens pecked more often at the ladder during the probe trials. The results suggest that the avian and mammalian visual systems operate along similar principles when dealing with the problem of solving occlusion indeterminacy in chromatically homogeneous patterns.

AB - Two chromatically identical patterns, a diamond and a ladder, were shown on a computer touchscreen. Domestic hens were reinforced for pecking at the pattern that was the highest up on a grid that provided pictorial depth information, i.e. on the pattern that to a human appears as being the furthest away. Every tenth trial was a non-rewarded probe trial with the two patterns partially overlapping. In the absence of other cues depth stratification can occur on the basis of a minimization of interpolated occluding contours. In humans the diamond is usually perceived to be in front of the ladder because shorter interpolated contours are needed to account for the occlusive effect of the diamond on the ladder. The hens pecked more often at the ladder during the probe trials. The results suggest that the avian and mammalian visual systems operate along similar principles when dealing with the problem of solving occlusion indeterminacy in chromatically homogeneous patterns.

KW - Chicken

KW - Occlusion

KW - Perception

KW - Petter's rule

UR - http://www.scopus.com/inward/record.url?scp=0000617007&partnerID=8YFLogxK

U2 - 10.1007/s100710050038

DO - 10.1007/s100710050038

M3 - Journal article

AN - SCOPUS:0000617007

VL - 2

SP - 181

EP - 185

JO - Animal Cognition

JF - Animal Cognition

SN - 1435-9448

IS - 4

ER -