Selective effects of post-imprinting anaesthesia on choice-test behaviour

Day-old chicks which are submitted to a halothane anaesthesia immediately after a 10 min. exposure to a moving model are less likely than non-treated chicks to approach this model in subsequent tests given 24 and 48 hours later. They may be unable to approach any model or they may approach the other model presented in the test situation. Modulation of responses at test depends on strength of imprinting which itself depends on attractiveness of the model and amount of following displayed during the exposure session. Results of this experiment corroborate previous results showing disruptive effects of halothane anaesthesia on behaviour in imprinted chicks, effects which are stronger if chicks had a poor visuo-motor experience at exposure session. Imprinting as a gradual acquisition process is suggested by detailed analysis of results of control and treated chicks.