Exploratory behavior in the dog: Experiential or age dependent?

Two independent groups of dogs (41 cross‐sectional and 16 longitudinal) were tested either once or successively in a behavior arena at 5, 8, 12, or 16 weeks of age for exploration to novel stimuli. The stimulus situations were, respectively, an empty cage, rat in a cage, mirror, auditory click, toy puppy, and flashing light. In the cross‐sectional group at the early ages more time was spent with the rat‐in‐cage and flashing‐light stimuli than with others. No differences in exploration time to any stimuli were seen after 8 weeks. Both number of squares traversed and number of „yelps” seemed to fluctuate more with increasing age. In contrast, the longitudinal group showed an increase in exploration with re‐testing. More time was spent with the toy pup and flashing light at the early ages, whereas the mirror was interacted with more at 12 and 16 weeks. Activity increased upon re‐testing, whereas vocalization decreased significantly after the first exposure to the testing arena. An evaluation of the reaction of each pup to a human was done on the day prior to testing. Those dogs that interacted with a human were also more exploratory and less fearful of a novel environment than those not interacting with a human. Results are discussed in terms of experiential rather than maturational factors as enhancing or modifying exploratory behavior in the dog.