Effects of prior video stimulation on open-field behaviour in domestic chicks

Two experiments examined the effects of regular video stimulation on open-field behaviour in Ž . Ž . domestic chicks tested in the presence Experiment 1 or absence Experiment 2 of the familiar video image. In Experiment 1, socially housed chicks were either exposed daily from 2 to 8 days Ž . Ž . of age to the video image of a computer screensaver SS in their home cage, or not N . At 9, 10 or 11 days of age each chick was tested individually in a square, black open field with either the Ž . SS video or just a sheet of black card control, BC visible through a wire-mesh window in one of the walls. SS chicks approached the familiar video image sooner and spent longer near it than N ones. These findings are consistent with earlier reports that familiar SS images were attractive to domestic chicks in a two-choice runway test and they show that this phenomenon generalizes to include a one-choice open-field situation. Our observations that SS chicks also walked significantly more and tended to vocalize sooner than N ones regardless of the test situation suggested that previous video stimulation may have reduced their fear of this novel environment. This was tested in Experiment 2 in which group-housed chicks were either exposed for 40 min per day from Ž . 2 to 8 days of age to a composite video CV image of five screensavers in their home cage, or not Ž . control, C . All chicks were then tested individually in a uniformly black open field with no video present. Freezing was shown by fewer CV than C chicks. The CV chicks also showed shorter durations of freezing, they entered more areas of the open field and tended to vocalize sooner than those from the C group. These results support the suggestion that regular exposure to a complex CV image during the first week of life decreased chicks’ fear when they were subsequently placed in an unfamiliar environment. q 2000 Elsevier Science B.V. All rights reserved.