Authors: Susann Meyer Gerd Nürnberg Birger Puppe Jan Langbein
Publish Date: 2012/03/29
Volume: 15, Issue: 4, Pages: 567-576
Abstract
The ability to establish categories enables organisms to classify stimuli objects and events by assessing perceptual associative or rational similarities and provides the basis for higher cognitive processing The cognitive capabilities of farm animals are receiving increasing attention in applied ethology a development driven primarily by scientifically based efforts to improve animal welfare The present study investigated the learning of perceptual categories in Nigerian dwarf goats Capra hircus by using an automated learning device installed in the animals’ pen Thirteen grouphoused goats were trained in a closedeconomy approach to discriminate artificial twodimensional symbols presented in a fourchoice design The symbols belonged to two categories category I black symbols with an open centre rewarded and category II the same symbols but filled black unrewarded One symbol from category I and three different symbols from category II were used to define a discrimination problem After the training of eight problems the animals were presented with a transfer series containing the training problems interspersed with completely new problems made from new symbols belonging to the same categories The results clearly demonstrate that dwarf goats are able to form categories based on similarities in the visual appearance of artificial symbols and to generalise across new symbols However the goats had difficulties in discriminating specific symbols It is probable that perceptual problems caused these difficulties Nevertheless the present study suggests that goats housed under farming conditions have welldeveloped cognitive abilities including learning of openended categories This result could prove beneficial by facilitating animals’ adaptation to housing environments that favour their cognitive capabilitiesWe thank Katrin Siebert and Dieter Sehland for excellent technical and experimental help We are also grateful to three anonymous reviewers for commenting on an earlier version of the manuscript This work was supported by the Deutsche Forschungsgemeinschaft LA 1187/51
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