1. Introduction
Video playback is being increasingly used to study behavioural responses in a wide Ž
. variety of species, including jumping spiders e.g., Clark and Uetz, 1990 , Anolis lizards
Ž .
Ž .
Ž e.g., Macedonia et al., 1994 , sticklebacks e.g., Rowland et al., 1995 , chickadees e.g.,
. Ž
. Ž
. Baker et al., 1996 , zebra finches e.g., Adret, 1997 , pigeons e.g., Shimizu, 1998 and
Ž .
rhesus monkeys e.g., Platt and Novak, 1997 . These and other studies using video Ž
. stimulation are more fully described elsewhere D’Eath, 1998 .
More specifically, we know that chickens feed, dustbathe or withdraw when shown Ž
. video images of feeding
Keeling and Hurnik, 1993; McQuoid and Galef, 1993 , Ž
. Ž
dustbathing Lundberg and Keeling, 1997 or threatening conspecifics D’Eath and .
Dawkins, 1996 , and that they show appropriate anti-predator responses to videos of Ž
. ground and aerial predators
Evans and Marler, 1991, 1992; Evans et al., 1993 . Furthermore, video images are easily manipulated and controlled. Thus, they provide a
Ž potentially powerful tool for studying numerous aspects of chickens’ behaviour Evans
. and Marler, 1991; Jones, 1996 . In the present study, we focused on the effects of prior
video stimulation on the responses of domestic chicks placed in an unfamiliar situation Ž
. open field .
It is widely recognized that domestic chicks are attracted to familiar companions, objects, drawings and odours in otherwise novel situations and that their presence can
Ž reduce fear e.g., Bateson, 1964; Wilson and Rajecki, 1974; Zajonc et al., 1974; Jones,
. 1996; Jones and Roper, 1997 . We already know that chicks readily approach familiar
Ž .
videos of computer screensavers SS when these are presented in a novel two-choice Ž
. runway situation Jones et al., 1996, 1998 . The present study asked whether these
phenomena would generalize to include familiar video images presented in a different and intuitively more frightening situation. Therefore, we used an open field test. Though
Ž .
controversial Archer, 1973; Gray, 1979; Jones, 1987a , this test has been commonly Ž
used to estimate fear in a variety of species, including chickens Gray, 1979; Jones, .
1989; Boissy, 1995 . It involves separation from companions and exposure to a novel, Ž
. barren environment. Novelty is a potent fear elicitor Jones, 1987b, 1996 and the open
Ž .
field was considered more frightening than the runway Jones et al., 1996, 1998 because of its greater dissimilarity from the home cage in terms of dimension, colour
and type of flooring. We examined the open-field behaviour of chicks that had been regularly exposed to
video images. In Experiment 1, chicks were either exposed to a video of a single computer SS from 2 to 8 days of age or not. We then compared their approach towards a
window in one wall of an open field when the SS image was either visible through it or not. Regular video stimulation might be regarded as a form of environmental enrichment
Ž
. Platt and Novak, 1997 and one effect of enrichment in chickens is the reduction of
Ž .
underlying fearfulness Jones, 1996 . Therefore, in Experiment 2 we determined whether Ž
. regular exposure to a more complex video composite of five SS reduced chicks’ fear
of an open field even in the absence of the familiar video. Sex differences in the fear Ž
. reactions of domestic chicks are occasionally reported see Jones, 1987b . Therefore, an
arbitrary decision was made here and only females were used.
2. General methods
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