Saying “dog” as the result of seeing a dog is an example of the tact relationship. If we say “dog” either because we see the word “dog” or hear it spoken, then the relationship is either textual or echoic, respectively. These latter two cases would not be tacts because the prior controlling stimuli are not non-verbal stimuli.
A form of verbal behavior with the following features:
A verbal response
The controlling variable is a non-verbal stimulus, which is an object or event or a property of an object or event
The musculature with which the response is executed (vocal, written, gestural, etc.)
The modality of the stimulus (auditory, visual, gustatory, olfactory, etc.)
Whether or not there is any reinforcement for the current response
The “correctness” of the response