Orienting signifies “attention,” not terror, in the standard lab situation, and its gradual elimination with repeated stimulus presentation is regarded as “habituation”—as something boring, akin to automatic acclimation, adjustment or desensitization. Habituation is not a passive process, however, at least at higher cortical levels of processing. It just looks passive when observed under relatively trivial circumstances. It is in reality always the consequence of active exploration and subsequent modification of behavior, or interpretive schema. The (relatively) novel target laboratory tone, for example, is investigated for its underlying structure by the cortical systems involved in audition. These systems actively analyze the component elements of every sound. The subject is led to “expect” or predict one sort of sound and gets another. The unexpected other has indeterminate significance, in that particular context, and is therefore regarded as (comparatively) meaningful—threatening and promising. The unexpected tone is presented repeatedly. The exploratory subject notes that the repetitions signify nothing, in the context that defines the experimental situation (nothing punishing, satisfying, threatening or promising), and ceases to react. He has not merely “habituated” to the stimuli. He has mapped its context-dependent significance, which is zero. This process appears trivial because the experimental situation makes it so. In real life, it is anything but boring.
What happens if an animal encounters something truly unexpected—something that should just not be, according to its current frame of reference or system of belief? The answer to this question sheds substantial light on the nature of the orienting reflex, in its full manifestation. Modern experimental psychologists have begun to examine the response of animals to natural sources of mystery and threat. They allow the animals to set up their own environments, realistic environments, and then expose them to the kinds of surprising circumstances they might encounter in real life. The appearance of a predator in previously safe space (space previously explored, that is, and mapped as useful or irrelevant) constitutes one type of realistic surprise. Blanchard and colleagues describe the naturalistic behavior of rats, under such conditions: