When someone engages in the behavior of saying “dog,” for example, they produce sound waves that result in an auditory stimulus that can be heard either by someone else or the speaker themself. The auditory stimulus “dog” is a verbal stimulus.
A physical energy change capable of affecting an organism’s sensory receptors that has the following features:
It has a specific form or pattern which, as a unit, has controlling effectiveness
It is the result of verbal behavior
Modality: auditory, visual, etc.
Dynamic characteristics such as size, intensity, etc.
Function: discriminative, reinforcing, punishing, etc.