For example, someone says “horse” and as a result of that auditory stimulus, you also say “horse.” Formal similarity exists in this case between the auditory stimulus “horse” and the response-product of the vocal response “horse.” The pattern of the auditory stimuli is the same, with the “h” sound at the beginning and the “s” sound at the end.
A relationship between a stimulus that evokes a response and the response-product of that response with the following features:
The stimulus and the response-product are both in the same modality (e.g., they are both visual or they are both auditory)
Their physical patterns or sequences resemble one another (e.g., they may look or sound alike)
Specific formal or dynamic features of the stimulus and the response-product
The number of additional formal or dynamic features resembling one another