[The influence of object sort and early experience on the discrimination learning in domestic chickens]

Main subject of the reported investigation is the question in which way the acquisition of a conditional discrimination is modified on the one hand by the kind of objects presented, on the other hand by early experience. 40 newly hatched chickens grew up either with all the wooden eggs or cubes used for training and test, or without these objects, or in a 'natural' (enriched) environment. The results prove an influence of the kind of objects--cubes are discriminated twice or three times as fast as wooden eggs--but no effects of the different environments on acquisition (number of trials for reaching learning criterion). Results are discussed under aspects of species-specific constraints on learning.