Understanding the nature of genetic influences and genotype-environment interactions in the development of a visually guided behavioral phenotype, and probing the neurophysiological mechanisms of coding and processing visual information in the vertebrate brain are the long-term objectives of this project. Its experimentations concentrate on gene effects and gene-environment interactions in the visual preferences and related behavioral developments of newly hatched and maturing quail chicks (C coturnix japonica). Short-term goals include (1) to develop procedures for identifying phenotypic units and manipulating individual variations of the quail's approach-choices between pairs of simple visual stimuli, (2) to probe the sources of individual variations of these behaviors, in relation to genotypes, experiences, and interactions between genotypes and experiences, (3) to map in genetically selected populations the functions and interactions of preferential responses to systematically varied light wavelengths, stimulus brightnesses, and temporal and spatial patterns of visual stimuli, and (4) to develop techniques for probing the neurophysiological correlates and mechanisms of genetic and environmental influences in the coding and processing of stimulus information in these behaviors.