Sources of Individual Variations in the Naive Approach Preferences of Quail Chicks: Age, Stimulus Intensity, and Genotypes

AbstractVariations in the early approach choices of naive quail chicks (C. coturnix japonica) were studied in relation to stimulus colours, stimulus intensities, age of subjects, and genotypes. Binary choices were tested at 7 hrs, 27 hrs, and 47 hrs of post-hatch age by a pair of coloured stimuli (blue and red) of identical photopic intensities (2.0 lux) and a pair of white stimuli of different intensities (20.0 lux vs 2.0 lux). Subjects were drawn from a genetically unmanipulated control population and from two genetic lines that were bidirectionally selected for choices between blue and red. Genetic controls showed very high preference of blue over red at 7 hrs of age, decreased blue preference at 27 hrs, and a slight preference of red over blue by 47 hrs. The two genetic lines showed significant modifications of colour choices by selection without showing corresponding changes in age effects. Both the control and the selected subjects showed preference of the higher intensity white stimulus, but this preference did not change with age. It was concluded that the gene effects in naive colour preferences are not related to age effects, nor to preferences between intensities of stimuli.