Object permanence is the notion that objects continue to exist even when they are out of an observer’s sight. In mammals, the highest stage of object permanence (Stage 6) has been observed only in primates, whereas other species have shown difficulty in following once-hidden objects, particularly when complex movements are involved. We conducted four experiments to examine the ability of dwarf goats to mentally represent once-hidden objects. In Experiment 1, we investigated whether dwarf goats are prone to commit the A-not-B or perseveration error which is commonly used as a measure for self-control. Subjects here continue to search for an object that was repeatedly hidden and successfully found at location A in previous trials at that position, even if it has been hidden then in full sight at location B. Experiments 2-4 investigated their ability to track the movements of hidden objects in a crossed transposition task. Here, a reward was hidden in one of two hiding locations. After baiting, both of the locations were changed in a crossed manner to see if the subjects were able to follow the baited one and choose it at the new position. The setup of Experiments 2-4 varied to examine which strategies and modifications may influence the performance of the subjects. The results of Experiment 1 suggest that dwarf goats only show a small prevalence to commit the A-not-B error. In the transposition tasks, the goats showed little to moderate success when both of the hiding locations were identical (Experiment 2 and 4) but a number of goats solved the task when the two hiding locations varied in colour and shape (Experiment 3). Although other factors, such as the movement and the side of the baited cup influenced the goats´ decision making, the results provide the first evidence that dwarf goats might be able to keep track of hidden objects that cross paths during transposition by encoding visual feature cues.
Nawroth, C., von Borell, E., & Langbein, J. (2015). Object permanence in the dwarf goat (Capra aegagrus hircus): perseveration errors and the tracking of complex movements of hidden objects. Applied Animal Behaviour Science, 167, 20-26.