Experience-induced modulation of the use of spatial information in the domestic chick

Abstract

We examined whether experience of opaque or transparent screens modulates the use of spatial cues by domestic chicks. From 10-12 days of age, chicks could lose sight of an imprinting stimulus or their cagemate in cages with opaque screens, but were largely unable to do so in cages with transparent screens. Chicks were then trained to find the imprinting stimulus behind one of two screens. Unrewarded probe tests were presented to chicks with the apparatus rotated by 180° so that proximal (intra-apparatus) and distal (extra-apparatus) cues indicated opposite sides of the apparatus. In tests with two distinctly different screens, chicks using the left eye (LES) chose the distal side more than the proximal side, whereas chicks using the right eye (RES) chose the proximal side more than the distal side. When using both eyes (BIN) in tests with different screens, chicks reared in cages with opaque screens were quicker in making a choice, and tended to choose the screen on the distal side more often than chicks reared in cages with transparent screens. Chicks reared in cages with opaque screens failed to make a choice less often than chicks reared in cages with transparent screens in BIN tests with different screens and in monocular tests with identical screens. The results suggest that chicks using the LES are less easily disrupted by conflicting spatial cues than chicks using the RES, and that experience of visual barriers from 10-12 days of age improves the chick's ability to attend to distal cues.