Which verbal operant refers to describing something in the environment?

The verbal operant that refers to describing something in the environment is the tact. A tact is a type of verbal behavior in which an individual labels or comments on an object, event, or situation in their environment. It is initiated by a stimulus from the environment that evokes a response, allowing the individual to express their observations or experiences, often leading to social reinforcement. For example, if someone sees a dog and says "dog," they are tacting. This response connects language with the environment, facilitating communication and interaction.

The other verbal operants, while they are foundational to understanding language development, do not specifically pertain to describing environmental stimuli in the same way. A mand involves requesting or demanding something, an echoic refers to repeating what someone else has said, and an intraverbal is when a person responds to another person's verbal behavior, typically in a conversation without direct environmental prompts. Each of these operants plays an essential role in language use but does not focus on labeling or describing as the tact does.