Important characteristics of Michael's (1982) definition a duplic:
General examples include: echoing what someone else says and copying a text.
(The response to be analyzed is in bold text.)
The first item is not an example of a duplic. The speaker is Jack. He did something (said "funny") and his behavior produced a reinforcing consequence (Jill's reaction). We classify his behavior as verbal because its reinforcing consequence was mediated by a listener (Jill). Jack's behavior was likely under the control of an SD (Jill's funny face). Let us assume that this SD is verbal, in the sense that Jill making a funny face occurred because of past mediated reinforcing consequences. Even so, the SD (visual stimulus) and the response product (auditory stimulus) do not have formal similarity.
The second item is an example of a duplic. Again, the speaker is Jack. He did something (made a funny face) and his behavior produced a reinforcing consequence (Jill's reaction). We classify his behavior as verbal because its reinforcing consequence was mediated by a listener (Jill). Jack's response was likely under the control of an SD (Jill making a funny face); also, the SD (visual stimulus) and the response product (visual stimulus) have formal similarity. If we assume, as we did above, that Jill's funny face is a verbal SD, then this example contains all three defining features of a duplic.