Final answer:
The dog's behavior is an example of classical conditioning, where it associates the word 'speak' with the action of sitting instead of barking. To teach the new trick, Mark can gradually associate the word 'speak' with the act of barking by providing positive reinforcement.
Step-by-step explanation:
The dog's behavior is an example of classical conditioning. Classical conditioning is a type of learning where an organism associates a neutral stimulus with a meaningful stimulus, leading to a response.
In this case, the dog has been conditioned to associate the word 'sit' with the action of sitting, and the word 'speak' with the action of sitting. This is because the dog has received reinforcement (treats) when it sits after hearing 'sit', but not when it sits after hearing 'speak'.
To teach the dog the new trick of barking when Mark says 'speak', Mark should start by providing positive reinforcement (treats) whenever the dog makes any vocalization. Gradually, he can start associating the word 'speak' with the act of barking by saying 'speak' and then immediately encouraging the dog to bark by making a vocalization himself. Over time, the dog will learn to associate the word 'speak' with the action of barking instead of sitting.