Final answer:
When adding a verbal cue to a dog's behavior that is already prompted by a hand signal, start by saying the command before presenting the signal, then reward the dog each time it correctly responds. Gradually phase out the hand signal while consistently using the verbal command, reinforcing the behavior with praise or treats.
Step-by-step explanation:
To add a verbal cue to a dog’s behavior that it is already offering in response to a hand signal, you will want to integrate the verbal command with the established hand signal. Start by clearly saying the verbal cue ('down' in this case) just before you present the hand signal that the dog already knows. This pairs the verbal command with the existing visual cue. Over time, with practice and consistency, the dog will begin to anticipate the hand signal when it hears the verbal command, eventually recognizing the verbal cue alone as a prompt for the action. To further reinforce the association, immediately reward the dog with praise or a treat after it successfully executes the behavior following the verbal cue. This positive reinforcement helps the dog confirm the connection between the verbal command and the desired action. Remember to also phase out the hand signal gradually, starting to delay it slightly after the verbal cue until the dog reliably responds to the verbal cue alone.