What learning process results in a dog shortening its stride when approaching closely placed jumps?

The learning process in which a dog shortens its stride when approaching closely placed jumps is known as adaptation. In this context, adaptation refers to the ability of the dog to adjust its behavior based on previous experiences and the physical demands of the situation. As the dog encounters closely placed jumps repeatedly, it learns to modify its stride to navigate the obstacles more effectively and safely. This process involves not just a basic reaction, but a learned adjustment intended to enhance performance or prevent mistakes, which illustrates the essence of adaptation in behavioral learning.

Other processes listed, such as habituation and sensitization, are focused on responses to stimuli rather than adjustments in behavior for specific tasks. Habituation is the decrease in response to a repeated, non-threatening stimulus, while sensitization involves an increased response to a stimulus after a strong initial reaction. Learned irrelevance refers to a phenomenon where an animal stops paying attention to a stimulus that is no longer relevant, which does not apply in the context of adjusting movement for jumps. Therefore, adaptation is the most appropriate term to describe the process of the dog shortening its stride in this scenario.