The effect of various durations of enforced exposure to a stimulus object on the reversibility of the following response in White Peking ducklings

Abstract

The purpose of this investigation was to test Salzen's neuronal model hypothesis of imprinting. According to this model imprinting is the process of acquiring a special type of perception. The process of forming the neuronal model should take at least 24 hours. The more established the model the better it should withstand interference from other stimulus patterns. If, however, a subject is forcibly exposed to a new stimulus object for some period of time in excess of 24 hours the neuronal model should adapt and the subject should respond positively to the new pattern of stimulation. The present research used White Peking ducklings as subjects and involved the following experimental design. Six different groups of four subjects each were raised with one of two stimuli for varying periods of time and then tested for a preference. An equal period of time was then spent with a different stimulus object and another preference test administered. If the subject's preference was reversed, it was concluded that reversibility had occurred. There were two 12-hour groups, two 24-hour groups, and two 72-hour groups. These labels designated the length of time that each group was raised with one of two stimulus objects before being exposed to the other stimulus object for an equal period of time. This procedure was used to test for any innate preferences that the subjects may have had for either of the stimulus objects. The results of the present research did not provide statistical support for Salzen's model in the White Peking duckling. The results indicated that the stimulus objects used in this study were equivalent in their ability to elicit the following response. In addition, it appears that older subjects follow a stimulus object more than younger subjects. In general, subjects followed more on the second preference test than they did on the first preference test. Activity level seems to account for this increased following, both within and between preference tests. The number of subjects that showed a preference for the object they were initially exposed to in their home cages was not statistically reliable. Few subjects reversed their initial preferences on the second preference test. The number of subjects that did reverse their initial preferences did not differ significantly from the number of subjects that did not reverse their initial preferences.