The last word in a line of poetry is often the function of more than one variable. In the lines from Shakespeare, “Golden lads and girls all must, as chimney sweepers, come to dust,” the phrase “come to dust” is multiply controlled.
A situation with the following features:
There is a single response form
The response is simultaneously strengthened by two or more controlling variables
Response topography
The type of controlling variable (stimulus or establishing operation)
The specific number of multiple variables
Whether or not the current response is followed by reinforcement