What is an example of an antecedent variable in verbal operants?

An antecedent variable in verbal operants refers to a condition or stimulus that occurs before a response and sets the stage for that response to happen. In the context of verbal behavior, antecedents can trigger verbal operants like mands or tacts.

The option mentioning a physical object present in the environment is a clear example of an antecedent variable because it serves as a stimulus that may elicit a response. For instance, if a child sees a toy (the physical object), this could prompt them to label it verbally or request it. The presence of an object creates an opportunity for communication to occur, illustrating the role of antecedent stimuli in verbal operants.

The other options focus on different aspects that do not represent antecedent variables as clearly. For example, an expression of disbelief pertains more to a reaction rather than a condition that initiates a behavior, while a question asked by someone else could create a conversational context, but it is more of a prompt than an event setting the stage for an operant. Immediate reinforcement relates to the consequences following a behavior, which is not an antecedent but rather a result of a previous action.