blocking

n. 1. In classical conditioning the prevention or reduction in the strength of an association between a stimulus and response by the prior presentation of another stimulus. Thus if a dog hears a tone and then a buzzer of equal sensory salience shortly before being fed, at each meal the dog will quickly begin to salivate when it hears the tone alone but will not do so or will do so less if it hears the buzzer alone. 2. An inferred process causing a sudden interruption in speech, thought, or other activities without conscious cause.