Similarity of approach and pecking preferences for spectral stimuli in domestic chicks: absence of a mirror-image relation.

The results of Schaefer and Hess showing that White Rock chicks described mirror-image response functions to spectral stimuli in approach and pecking behavior could not be replicated using Cornish-Cross chicks under more controlled conditions. Our results showed similar blue-orange bimodal functions for both behavioral responses, resembling the approach data of Schaefer and Hess and the earlier pecking data of Hess and others, but not the pecking data reported by Schaefer and Hess.