Likewise, the sign may be on, but you are not thirsty. Suddenly a small fire breaks out and you start pushing the button like crazy. The fire is an establishing operation. The fire is not a signal that you can now get water if you push the button; so it is not a discriminative stimulus. The sign is the discriminative stimulus. If the sign goes off, then you can’t get water; if the fire goes out (but the sign is still on), you can still get water. The sign discriminates between when button pushing will get water and when it won’t. The fire determines whether or not water would be an effective reinforcement for pushing the button.
An environmental change or event with the following features:
Precedes the response to which it is functionally related
Increases the effectiveness of a particular stimulus change as reinforcement
The type of environmental event
The cause of the environmental event
The type of stimulus that gains reinforcing effectiveness