Animal Cognition

, Volume 12, Issue 3, pp 511–526

Local rather than global processing of visual arrays in numerosity discrimination by pigeons (Columba livia)

Original Paper

DOI: 10.1007/s10071-009-0212-5

Cite this article as:
Emmerton, J. & Renner, J.C. Anim Cogn (2009) 12: 511. doi:10.1007/s10071-009-0212-5

Abstract

A series of experiments investigated which stimulus properties pigeons use when they discriminate pairs of visual arrays that differ in numerosity. Transfer tests with novel stimuli confirmed that the birds’ choices were based on relative differences in numerosity. However, pigeons differed from other species in the non-numerical cues that affected their choices. In human and non-human primates, numerical discrimination is often influenced by continuous variables such as surface area or overall stimulus brightness. Pigeons showed little evidence of using those cues, even when summed area and brightness had been correlated with numerosity differences and reward outcome. But when array-element sizes were asymmetrically distributed across numerosities, the birds readily utilized information about item sizes as an additional discriminative cue. These novel results are discussed in relation to pigeons’ tendency to focus on local, rather than global dimensions when they process other non-numerical complex visual stimuli. The findings suggest there may be inter-specific differences in the type of perceptual information that provides the input stage for mechanisms underlying numerical processing.

Keywords

Numerosity discrimination Size cues Local vs. global visual processing Pigeon 

Supplementary material

10071_2009_212_MOESM1_ESM.doc (34 kb)
Supplementary material 1 (DOC 33 kb)

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of Psychological SciencesPurdue UniversityWest LafayetteUSA

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