Weak General but No Specific Habituation in Anticipating Stimuli of Presumed Negative and Positive Valence by Weaned Piglets

Everyday experience shows that getting used to negative events is difficult, whereas positive events are quickly taken for granted. This is relevant for basic questions on how we and other animals deal with emotional events. It has also practical implications because we would like to avoid negative events as much as possible and increase the positive events for animals in our care. Here, we repeatedly treated pairs of piglets with a variety of presumed negative, intermediate and positive events and measured their restlessness as well as the reaction of the autonomic nervous system, while the piglets expected these events. We found limited evidence that the reactions of the piglets changed in a systematic way with more repetitions of the different events. Both our experimental set-up and measurements have been used in similar ways before. Therefore, it is likely that we did not find a consistent pattern because we had not correctly assessed the negativity-positivity of the events used or their intensity from the point of view of the piglets