Swedish University of Agricultural Sciences, Skara, Sweden
A difficulty in the study of social behaviour is the dynamic aspect of the relationship. The responses of a test animal to a stimulus animal can be recorded, but the responses of the test animal can in turn influence the behaviour of the stimulus animal, making replication difficult. Furthermore, the stimulus animal may not always behave in the desired way and only behaviour patterns that are easily manipulated can be used. Using a video image of an animal as the stimulus is one potential method to eliminate these problems. Showing video or film images to animals is not new, but only more recently have they been used in a controlled experimental way. Spiders have been shown to attack images of prey and cockerels have been shown to modify their antipredator behaviour in an appropriate way when able to see a video image of a hen or when the predator is computer-generated. Video images of birds feeding have also been demonstrated to influence feeding behaviour. Thus video images have been useful in studies related to basic behavioural responses such as avoiding predation and feeding. Video images have been less useful in studies related to higher behavioural responses, such as individual recognition, and it is not yet clear whether these video images are perceived as equivalent to real objects. Nevertheless, it is proposed that when used in an appropriate way, letting animals watch video images of conspecifics is a useful tool for the study of social behaviour.