What does the NO marker signify?

• A. It informs the MWD that it performed an incorrect response; normally followed by a physical correction
• B. It signals the dog did well
• C. It resets the dog
• D. It ends training

Answer: (A)

Markers in MWD training provide immediate feedback on the dog’s actions. The NO marker signals that the dog’s current response is incorrect or undesired at that moment. It acts as negative feedback, letting the dog know that this particular action won't be reinforced, and it’s typically followed by a corrective step—such as resetting the task or guiding the dog to perform the correct response—so the dog can try again and earn the positive marker for the correct action. It’s not a signal that the dog did well, and it’s not the same as ending training; it’s a tool for shaping behavior. For example, if the dog chooses the wrong container in a scent task, the handler uses the NO marker to indicate the error, then redirects the dog to the correct target and reinforces the correct choice with a positive marker.