If you see an actual alligator and say “alligator,” the type of control is thematic because there is no point-to-point correspondence between the stimulus and the response. The head of the alligator does not control the “al” and the tail does not control the “gator.”
When a controlling variable evokes a response and has the following features:
There is NO point-to-point correspondence between the controlling variable and the response
Whether or not there is formal similarity between the controlling variable and the response
Formal characteristics of either the controlling variable or the response
Dynamic characteristics of either the controlling variable or the response