Generalization of color by chickens: experimental observations and a Bayesian model

Colaco Osorio, Daniel, Baddeley, RJ and Jones, CD (2007) Generalization of color by chickens: experimental observations and a Bayesian model. American Naturalist, 169. S27-S41. ISSN 0003-0147

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Sensory generalization influences animals' responses to novel stimuli. Because color forms a perceptual continuum, it is a good subject for studying generalization. Moreover, because different causes of variation in spectral signals, such as pigmentation, gloss, and illumination, have differing behavioral significance, it may be beneficial to have adaptable generalization. We report on generalization by poultry chicks following differential training to rewarded (T+) and unrewarded (T) colors, in particular on the phenomenon of peak shift, which leads to subjects preferring stimuli displaced away from T. The first three experiments test effects of learning either a fine or a coarse discrimination. In experiments 1 and 2, peak shift occurs, but contrary to some predictions, the shift is smaller after the animal learned a fine discrimination than after it learned a coarse discrimination. Experiment 3 finds a similar effect for generalization on a color axis orthogonal to that separating T+ from T. Experiment 4 shows that generalization is rapidly modified by experience. These results imply that the scale of a perceptual ruler is set by experience. We show that the observations are consistent with generalization following principles of Bayesian inference, which forms a powerful framework for understanding this type of behavior.

Item Type: Article
Additional Information: Develops earlier work from my lab. on sensory generalization. Provides a strong theoretical framework and opens new experimental approaches. Relates work on cognition to understanding evolution of animal signals.
Schools and Departments: School of Life Sciences > Evolution, Behaviour and Environment
Depositing User: Daniel ColacoOsorio
Date Deposited: 06 Feb 2012 20:21
Last Modified: 06 Feb 2012 21:55
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