Final answer:
When pointing to a cat and saying it is not a dog, this serves as a Negative instance of the dog concept, helping to differentiate and define the boundaries of the concept.
Step-by-step explanation:
Pointing to a cat and saying, 'This is not a dog,' is an example of a Negative instance of the dog concept. In psychology, specifically in the study of concepts and categorization, a negative instance refers to an example that is identified as not belonging to a particular category or concept. This contrasts with a positive instance, which would be an example that clearly fits within the defined category. By identifying what a dog is not, one is providing information that helps to understand the boundaries of the 'dog' concept. A negative instance helps in the cognitive process of differentiating between what is included and excluded from a particular concept.